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Biomedical subjects

M Nobuyoshi

Publications and source records attributed to M Nobuyoshi.

At least 55 records · Page 3Linked to original sources
PubMed1997

Successful directional atherectomy of de novo coronary lesions assessed with three-dimensional intravascular ultrasound and angiographic follow-up.

Recent histopathologic and intravascular ultrasound (IVUS) data indicate that inadequate compensatory enlargement of atherosclerotic lesions contributes to the development of significant arterial stenoses. Such lesions may contain less plaque, which may have implications for atheroablative interventions. In this study, we compared lesions with (group A, n = 16) and without inadequate compensatory enlargement (group B, n = 30) as determined by IVUS. The acute results and the follow-up lumen dimensions of angiographically successful directional coronary atherectomy procedures were compared. Inadequate compensatory enlargement was considered present when the preintervention arterial cross-sectional area at the target lesion site was smaller than that at the (distal) reference site. Three-dimensional IVUS analysis and quantitative angiography were performed in 46 patients before and after intervention. IVUS measurements included the arterial, lumen, and plaque (arterial minus lumen) cross-sectional areas at the target lesion site (i.e., smallest lumen site) and the (distal) reference site. Angiographic follow-up was performed in 42 patients. Preintervention and postintervention angiographic measurements and IVUS lumen cross-sectional area measurements were similar in both groups. However, at follow-up, the angiographic minimum lumen and reference diameters were significantly smaller in group A compared with group B (1.71 +/- 0.47 mm vs 2.14 +/- 0.73 mm, p <0.03, and 2.97 +/- 0.29 mm vs 3.39 +/- 0.76 mm, p <0.02; group A vs B). The data of this observational study suggest that lesions with inadequate compensatory enlargement, as determined by IVUS before intervention, may have less favorable long-term lumen dimensions after directional coronary atherectomy procedures.

Adult↗
PubMed1997

Contemporary percutaneous treatment of unprotected left main coronary stenoses: initial results from a multicenter registry analysis 1994-1996.

BACKGROUND: Coronary artery bypass surgery (CABG) has been considered the therapy of choice for patients with unprotected left main (ULMT) coronary stenoses. Selected single-center reports suggest that the results of percutaneous intervention may now approach those of CABG. METHODS AND RESULTS: To assess the results of percutaneous ULMT treatment from a wide variety of experienced interventional centers, we requested data on consecutive patients treated after January 1, 1994, from 25 centers. One hundred seven patients were identified who were treated either electively (n=91) or for acute myocardial infarction (n=16). Of patients treated electively, 25% were considered inoperable, and 27% were considered high risk for bypass surgery. Primary treatment included stents (50%), directional atherectomy (24%), and balloon angioplasty (20%). Follow-up was 98.8% complete at 15+/-8 months. Results varied considerably, depending on presentation and treatment. For patients with acute myocardial infarction, technical success was achieved in 75%, and survival to hospital discharge was 31%. For elective patients, technical success was achieved in 98.9%, and in-hospital survival was strongly correlated with left ventricular ejection fraction (P=.003). Longer-term event (death, infarction, or bypass surgery) -free survival was correlated with ejection fraction (P<.001) and was inversely related to presentation with progressive or rest angina (P<.001). Surgical candidates with ejection fractions > or = 40% had an in-hospital survival of 98% and a 9-month event-free survival of 86+/-5%, whereas patients with ejection fractions < 40% had 67% and 22+/-12% in-hospital and 9-month event-free survivals, respectively. Nine hospital survivors (10.6%) experienced cardiac death within 6 months of hospital discharge. CONCLUSIONS: While results for selected patients appear promising, until early post-hospital discharge cardiac death can be better understood and minimized, percutaneous revascularization of ULMT stenosis should not be considered an alternative to bypass surgery for most patients. When percutaneous revascularization of ULMT is required, directional atherectomy and stenting appear to be the preferred techniques, and follow-up angiography 6 to 8 weeks after treatment is probably advisable.

Aged↗
PubMed1997

Interventional treatment for children with severe coronary artery stenosis with calcification after long-term Kawasaki disease.

BACKGROUND: About 4% of children with Kawasaki disease (KD) eventually develop ischemic heart disease, which is often associated with calcified stenosis. We assessed the utility of the percutaneous transluminal coronary rotational ablation (PTCRA) in children with coronary artery stenosis after KD. METHODS AND RESULTS: Four children (three boys and one girl; age, 12 to 13 years) with coronary artery stenosis underwent percutaneous transluminal coronary angioplasty (PTCA) and PTCRA 11.8+/-0.9 years after the onset of KD. Morphology of the coronary artery wall was evaluated by intravascular ultrasound imaging. In one patient, the targeted lesion for intervention was in the left anterior descending artery (90% stenosis); in the other three patients, it was in the middle of the right coronary artery (75% to 90% stenosis). PTCA failed in three patients because of severe stenosis with calcification. However, PTCRA proved effective, with stenosis rates reduced from 90% to 25%. Follow-up coronary angiography performed 4 months after the procedure demonstrated no restenosis, but mild aneurysms occurred in two patients. CONCLUSIONS: This study suggests that PTCRA is useful for revascularizing coronary arteries with severe stenosis and calcification as long-term sequelae of KD. Intravascular ultrasound imaging is useful in assessing the coronary artery wall pathology and in selecting the best treatment intervention.

Adolescent↗
PubMed1997

Remodeling of human coronary arteries undergoing coronary angioplasty or atherectomy.

BACKGROUND: Recently, long-term constriction of the vessel has been suggested as an alternative mechanism of restenosis after coronary angioplasty. METHODS AND RESULTS: To understand remodeling of human coronary arteries undergoing coronary angioplasty or atherectomy, serial intravascular ultrasonographic examinations were performed at preintervention and postintervention examinations and at 24 hours, 1 month, and 6 months. Complete serial data were obtained in 61 lesions (balloon angioplasty, 35 lesions; directional atherectomy, 26 lesions). Lumen area improved from 6.81+/-2.24 mm2 after intervention to 8.22+/-2.79 mm2 at 1 month (P=.0001) and decreased to 4.88+/-2.86 mm2 at 6 months (P=.0001). Vessel area enlarged from 17.32+/-5.35 mm2 after intervention to 19.39+/-5.33 mm2 at 1 month (P=.0001) and decreased to 16.33+/-5.54 mm2 at 6 months (P=.0001). Plaque+media area increased significantly from postintervention examination to 24 hours (10.51+/-4.38 versus 10.96+/-4.49 mm2, P=.0008) and from 24 hours to 6 months (10.96+/-4.49 versus 11.45+/-4.45 mm2, P=.03). Changes in lumen area in each study interval correlated more closely with changes in vessel area than with changes in plaque+media area. Restenotic lesions compared with nonrestenotic lesions had a greater decrease in the vessel area between 1 month and 6 months (-4.33+/-2.73 versus -2.49+/-2.15 mm2, P=.006) and greater increase in the plaque+media area both within 24 hours (0.84+/-1.22 versus 0.27+/-0.38 mm2, P=.04) and between 24 hours and 6 months (1.19+/-2.19 versus 0.18+/-1.46 mm2, P=.04). CONCLUSIONS; Remodeling after coronary angioplasty or atherectomy was characterized by early adaptive enlargement and late constriction of the vessel.

Aged↗
PubMed1997

Transcription regulation of the PDGF A-chain gene by first intron elements.

A cis-acting regulatory region within the first intron of the human platelet-derived growth factor (PDGF) A-chain gene has been identified that functions to negatively regulate transcription of PDGF A-chain promoter/CAT reporter constructs in both A172 and HeLa cells and that functions independent of position, orientation, and promoter context. Further dissection of this region revealed several independently acting negative regulatory elements that exhibited cell-type specificity. These results suggest that the first intron of the PDGF A-chain gene contains negative regulatory elements that may cooperate to regulate the cell-type specific expression of the PDGF A-chain gene.

Cloning, Molecular↗
PubMed1997

Initial experience with the Cordis stent: analysis of serial angiographic follow-up.

To evaluate the efficacy of the more flexible Cordis stent, a prospective angiographic follow-up study was performed. Implantation of the Cordis stent was attempted in 99 consecutive patients with 103 native coronary lesions from January 1994 to July 1995. Clinical success, defined as final diameter stenosis of < 50% without death, bypass surgery, or Q-wave myocardial infarction, was achieved in 88% of the patients. There were no in-hospital deaths. In-hospital subacute stent occlusion occurred in only one case. Follow-up angiograms were obtained in 86 (95%) eligible lesions. The minimal luminal diameter improved from 1.03 +/- 0.31 to 2.82 +/- 0.31 mm, but started to decrease at 1 mon (2.57 +/- 0.24 mm), and continued to decrease throughout the 6 mon (2.00 +/- 0.61 mm), the biggest reduction being between 1 and 3 mon (-0.57 +/- 0.50 mm). Angiographic restenosis (stenosis > or = 50%) occurred in 23% of the lesions; a revascularization procedure of the target lesion was required in 12% of the patients. Multivariate analysis identified age, diabetes mellitus, and preprocedural reference diameter to be predictors of angiographic restenosis. In conclusion, the Cordis stent can be implanted successfully with a low complication rate and a clinical outcome at least comparable to other stent studies.

Adult↗
PubMed1997

A prospective, randomized, double-blind multicenter trial of a single bolus injection of the novel modified t-PA E6010 in the treatment of acute myocardial infarction: comparison with native t-PA. E6010 Study Group.

OBJECTIVES: This prospective, randomized, double-blind multicenter trial evaluated the efficacy and safety of a single bolus injection of the novel modified tissue-type plasminogen activator (t-PA) E6010 in the treatment of acute myocardial infarction compared with that of native t-PA. BACKGROUND: E6010 is a novel modified t-PA with a prolonged half-life (t1/2 alpha > or = 23 min) compared with native t-PA (t1/2 alpha = 4 min). E6010 can be administered in patients as a single intravenous bolus injection, and early recanalization can be expected. METHODS: The efficacy of E6010 was compared with that of native t-PA in 199 patients with acute myocardial infarction who were treated within 6 h of onset in a prospective, randomized, double-blind multicenter trial. Patients were given either 0.22 mg/kg body weight of E6010 intravenously over 2 min or native t-PA (tisokinase) 28.8 mg or 14.4 million IU (10% of the total dose over 1 to 2 min, the remainder infused over 60 min). RESULTS: The primary end point was the recanalization rate of the infarct-related coronary artery at 60 min after the start of treatment. Time to reperfusion was shorter in the E6010 group than in the native t-PA group. Thrombolysis in Myocardial Infarction flow grade 2 or 3 recanalization at 15, 30, 45 and 60 min after administration was observed in 37%, 62%, 74% and 79% (95% confidence interval [CI] 70% to 87%) of the E6010-treated patients and in 14%, 32%, 50% and 65% (95% CI 55% to 74%) of native t-PA-treated patients, respectively (p = 0.032 at 60 min). CONCLUSIONS: The present study indicates that, compared with native t-PA, a single bolus injection of E6010 over 2 min produces a higher rate of early recanalization of the infarct-related coronary artery without fatal bleeding complications.

Aged↗
PubMed1997

A prospective, randomized evaluation of prophylactic intraaortic balloon counterpulsation in high risk patients with acute myocardial infarction treated with primary angioplasty. Second Primary Angioplasty in Myocardial Infarction (PAMI-II) Trial Investigators.

OBJECTIVES: A large, international, multicenter, prospective, randomized trial was performed to determine the role of prophylactic intraaortic balloon pump (IABP) counterpulsation after primary percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI). BACKGROUND: Previous studies have suggested that routine IABP use after primary PTCA reduces infarct-related artery reocclusion, augments myocardial recovery and improves clinical outcomes. METHODS: Cardiac catheterization was performed in 1,100 patients within 12 h of onset of AMI at 34 clinical centers. Clinical and angiographic variables were used to stratify patients undergoing primary PTCA into high and low risk groups. High risk patients were then randomized to 36 to 48 h of IABP (n = 211) or traditional care (n = 226). The study had 80% power to detect a reduction in the primary end point from 30% to 20%. RESULTS: There was no significant difference in the predefined primary combined end point of death, reinfarction, infarct-related artery reocclusion, stroke or new-onset heart failure or sustained hypotension in patients treated with an IABP versus those treated conservatively (28.9% vs. 29.2%, p = 0.95). The IABP strategy conferred modest benefits in reduction of recurrent ischemia (13.3% vs. 19.6%, p = 0.08) and subsequent unscheduled repeat catheterization (7.6% vs. 13.3%, p = 0.05) but did not reduce the rate of infarct-related artery reocclusion (6.7% vs. 5.5%, p = 0.64), reinfarction (6.2% vs. 8.0%, p = 0.46) or mortality (4.3% vs. 3.1%) and was associated with a higher incidence of stroke (2.4% vs. 0%, p = 0.03). IABP use did not result in enhanced myocardial recovery as assessed by paired admission to predischarge and 6-week rest and exercise left ventricular ejection fraction. CONCLUSIONS: In contrast to previous studies, a prophylactic IABP strategy after primary PTCA in hemodynamically stable high risk patients with AMI does not decrease the rates of infarct-related artery reocclusion or reinfarction, promote myocardial recovery or improve overall clinical outcome.

Angioplasty, Balloon, Coronary↗
PubMed1997

Remodelling and restenosis: intravascular ultrasound studies.

Remodelling, defined as a change in total vessel area, was demonstrated to be another important mechanism of restenosis after coronary angioplasty in a study utilizing intravascular ultrasound. In this study, remodelling was also demonstrated to be bidirectional (constrictive modelling and adaptive remodelling). A recent serial intravascular ultrasound study revealed that time course of remodelling after coronary angioplasty was typically biphasic; early (post-procedure-1 month) adaptive remodelling and late (1 month-6 months) constrictive remodelling. Remodelling after coronary angioplasty should be regarded not only as a cause of restenosis but also as a mechanism maintaining patency.

Angioplasty, Balloon, Coronary↗
PubMed1996

Serial angiographic follow-up after successful direct angioplasty for acute myocardial infarction.

This serial follow-up study was designed to identify the time course of reocclusion and/or restenosis after direct angioplasty for acute myocardial infarction. Direct angioplasty for acute myocardial infarction was attempted in 160 patients. Of the 141 patients who underwent successful reperfusion and were discharged, 137 (97%) were enrolled in this study. At the 3-week follow-up study (100% eligible), angiographic restenosis of the infarct-related artery was documented in 21 patients (16%), 9 (43%) of which were reocclusions. At 4 months in 100 patients (92% of those eligible), restenosis was newly documented in 28 infarct-related arteries (28%), 3 of which were reocclusions (11%). At 1 year in 64 patient (89% of those eligible), restenosis was newly documented in 5 infarct-related arteries (7.8%), with no reocclusions. The cumulative restenosis rate was 20% at 3 weeks, 43% at 4 months, and 47% at 1 year; when divided into occlusive and nonocclusive types, restenosis rates were 12% and 8.8% at 3 weeks and 14% and 29% at 4 months, respectively. Restenosis was most prevalent within the first 4 months and rarely occurred after that. When restenosis is manifested as reocclusion, it occurs earlier than in nonocclusive restenosis, often within 3 weeks.

Aged↗
PubMed1996

Altered expression of Pax-5 gene in human myeloma cells.

Recent phenotypic analysis of plasma cells showed that normal plasma cells do express the B-cell lineage-specific molecule CD19, but their malignant counterpart (myeloma cells) are CD19-. To clarify the meaning of loss of CD19 antigen on myeloma cells, we first compared the expression of CD19 and Pax-5 genes among B cells, normal plasma cells, myeloma cell lines, and primary myeloma cells, because the Pax-5 gene was reported to encode the transcriptional factor, B-cell-specific activating protein (BSAP), necessary for CD19 gene expression. Neither CD19 nor Pax-5 mRNA could be detected in those primary myeloma cells and cell lines, whereas normal plasma cells did express both CD19 and Pax-5 mRNA. Furthermore, we could confirm that BSAP-binding activity was not detected in the nuclear extract from CD19- myeloma cell line (KMS-5) but was detected in CD19+ B-cell line (Raji) by gel-shift assay. We further examined the expression of E2A and Id genes, because E2A and Id are considered to be positive and negative regulators in the expression of Pax-5 gene, respectively. However, no significant differences in the expression of these E2A and Id-2 genes could be observed between myeloma cells and normal plasma cells. Therefore, these data suggest that the altered expression of Pax-5, but not E2A or Id, is responsible for the loss of CD19 expression in human myeloma cells, although the underlying mechanism of the altered Pax-5 gene expression remains to be clarified.

Antigens, CD19↗
PubMed1996

Novel biochemical diagnostic method for aortic dissection. Results of a prospective study using an immunoassay of smooth muscle myosin heavy chain.

BACKGROUND: Aortic dissection is one of the most common aortic catastrophes. Although newer diagnostic methods as exemplified by image diagnostic techniques have greatly improved the diagnosis of aortic dissection, the diagnosis is still frequently missed today because the signs and symptoms of the disease are at times obscure. A reliable biochemical diagnostic method for aortic dissection would be beneficial. METHODS AND RESULTS: A novel biochemical diagnostic method for diagnosis of aortic dissection was developed that uses an immunoassay of monoclonal antibodies to smooth muscle myosin heavy chain. A prospective study was conducted to ascertain the usefulness of the method in the diagnosis of aortic dissection. Twenty-seven patients with aortic dissection admitted within the first 24 hours after onset were enrolled. Serial assay of serum smooth muscle myosin heavy chain showed significant elevations within the first 24 hours after onset of aortic dissection, with levels exceeding 10 ng/mL, with subsequent rapid reductions. The sensitivity of the assay within the first 12 hours was 90% with a specificity of 97%. Analysis of 65 patients with acute myocardial infarction showed that the method could accurately differentiate myocardial infarction from aortic dissection. CONCLUSIONS: The immunoassay of serum smooth muscle myosin heavy chain is a rapid and reliable biochemical method in the diagnosis of aortic dissection. The potential use of the method in clinical medicine is promising.

Aged↗
PubMed1996

Evidence that implicates the parathyroid hormone-related peptide in vascular stenosis. Increased gene expression in the intima of injured carotid arteries and human restenotic coronary lesions.

Proliferation of vascular smooth muscle cells (VSMCs) is considered to be one key event underlying the pathophysiology of restenosis after angioplasty. The parathyroid hormone-related peptide (PTHrP) and its receptor, a local autocrine and paracrine regulator of cellular growth in a variety of normal cell types, have been reported in the vicinity of VSMCs. To investigate how PTHrP might be involved in the process of neointimal formation after balloon angioplasty, we examined PTHrP expression in balloon-denuded rat carotid arteries and human coronary arteries that had been retrieved by directional atherectomy. In rat carotid arteries, the RNase protection assay and in situ hybridization demonstrated that PTHrP mRNA expression increased fourfold to sixfold 1 to 7 days after denudation and continued for 28 days, coincident with downregulation of PTH/PTHrP receptor mRNA expression. In situ hybridization and immunohistochemistry revealed that PTHrP expression in balloon-denuded carotid arteries was mainly localized to the neointima. To confirm the involvement of the PTHrP in human coronary artery restenotic lesions, immunohistochemical analysis of human coronary atherectomy specimens (23 primary and 10 restenotic lesions) was then performed. The number of intimal cells that expressed PTHrP protein was significantly higher in restenotic (407 +/- 53 cells/mm2; range, 143 to 739) than in stable angina (50 +/- 12 cells/mm2; range, 18 to 132; P<.05) or unstable angina (129 +/- 16 cells/mm2; range, 21 to 232; P<.05) specimens. These data demonstrate that PTHrP gene expression in VSMCs markedly increases during neointimal formation, supporting the hypothesis that PTHrP may play an important role in vascular stenosis as a regulator of VSMC proliferation.

Adult↗
PubMed1996

Beta ig-h3, a transforming growth factor-beta-inducible gene, is overexpressed in atherosclerotic and restenotic human vascular lesions.

Transforming growth factor-beta (TGF-beta) plays an important role in vascular lesion formation and possibly the renarrowing process ("restenosis") that occurs after balloon angioplasty. Secreted in a latent form by most cells, TFG-beta requires enzymatic conversion before it is biologically active. TGF-beta-inducible gene h3 (beta ig-h3) is a novel molecule that is induced when cells are treated with TGF-beta1. This study examined the expression of beta ig-h3 in normal and diseased human vascular tissue. To determine the expression pattern of beta ig-h3 in human arteries, immunocytochemistry was performed on tissue sections from (1) normal internal mammary arteries, (2) the proximal left anterior descending coronary artery (with minimal intimal thickening) of 15 patients aged 18 to 40 years, (3) primary and restenotic coronary lesions from 7 patients, and (4) fresh directional atherectomy tissue from 11 patients. A polyclonal antibody consistently immunodetected beta ig-h3 protein in endothelial cells of all vascular tissue. In normal coronary arteries of young individuals, beta ig-h3 protein was absent from the intima and media but was found in the subendothelial smooth muscle cells of some arteries with modest intimal thickening. In diseased arteries beta ig-h3 protein was more abundant in the intima than the media. Restenotic coronary lesions tended to show higher levels of immunodetectable beta ig-h3 protein, especially in areas of dense fibrous connective tissue. Beta ig-h3 protein was immunodetected in the cytoplasm of plaque macrophages as well as smooth muscle and endothelial cells. By using in situ hybridization on fresh directional atherectomy specimens, we found beta ig-h3 mRNA to be overexpressed by plaque macrophages and smooth muscle cells. Nondiseased human internal mammary arteries also expressed beta ig-h3 mRNA in endothelial cells but not in the smooth muscle cells of the normal intima and media. These results document the expression of beta ig-h3 in diseased human arterial tissue and support the hypothesis that active TGF-beta plays a role in atherogenesis and restenosis.

Adolescent↗
PubMed1995

Coronary lumen at six-month follow-up of a new radiopaque Cordis tantalum stent using quantitative angiography and intracoronary ultrasound.

To determine the reliability of geometric (edge-detection) quantitative coronary angiographic analysis (QCA) of restenosis within a new Cordis tantalum stent, QCA and intracoronary ultrasound (ICUS) measurements were compared in both an experimental restenosis model and in the clinical follow-up of patients. In the experimental series, Plexiglas phantom vessels with concentric stenosis channels ranging from 0.75 to 3.0 mm in diameter and with a reference diameter of 3.0 mm were imaged both before and after their insertion in tantalum stents. In the clinical series, the agreement of QCA and ICUS measurements were studied in 23 patients who had undergone coronary implantation of the new tantalum stent and in 23 patients who had undergone balloon angioplasty 6 months previously. The reliability of QCA declined in the presence of the radiopaque stent (accuracy of QCA decreased from -0.07 to -0.12 mm), whereas the reliability of lumen measurements by ICUS was independent of the presence of the radiopaque stent (-0.12 and -0.13 mm). Without the stent, the average minimal luminal diameter (MLD) obtained by QCA of the 1.00 mm Plexiglas vessel was 1.00 +/- 0.01 mm, and the 3.00 mm reference vessel diameter was 2.81 +/- 0.05 mm, providing a 64 +/- 1% diameter stenosis. After introduction of the stent, the average MLD and reference vessel diameter were 0.99 +/- 0.06 and 3.36 +/- 0.17 mm, respectively, providing a diameter stenosis of 71 +/- 2%. ICUS measurements (2.77 mm) of the reference vessel diameter (3.00 mm) were unaffected by the presence of the stent.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Angiography↗
PubMed1995

[Clinical application of 99mTc-tetrofosmin myocardial SPECT--a multicenter trial].

We performed a multicenter trial of 99mTc-tetrofosmin myocardial SPECT for the assessment of acute thrombolysis, pre and post elective PTCA and myocardial viability in comparison with 201Tl myocardial SPECT. The participants consisted of 212 patients at 44 institutions and the study lasted for 10 months. In assessing acute thrombolysis, the perfusion defect from the acute to subacute phase was reduced by 25% and that from the subacute to chronic phase by 10%. The mean perfusion defect score at subacute and chronic phase was correlated well with regional wall motion. The mean defect score during the subacute phase could predict future wall motion abnormalities. In assessing pre and post PTCA, 99mTc-tetrofosmin stress/rest myocardial SPECT could identify the changes of perfusion as in the case with successful PTCA and/or restenosis. In assessing the myocardial viability, 99mTc-tetrofosmin rest myocardial SPECT was superior to 201Tl redistribution, and equal to 201Tl reinjection method. In summary, we concluded that 99mTc-tetrofosmin is a powerful tool, with which to diagnose and manage patients with coronary artery diseases.

Adult↗