Search PubMed⌕ Search

Biomedical subjects

A Itoh

Publications and source records attributed to A Itoh.

At least 127 records · Page 7Linked to original sources
PubMed1997

Intraductal ultrasonography of the pancreas: development and clinical potential.

Intraductal ultrasound (IDUS) probes mounted with 30 MHz or 20 MHz transducers were evaluated in the diagnosis of 239 patients with pancreatic disease (including 48 cancers, 90 mucin-producing tumors, seven islet-cell tumors, two metastatic pancreatic tumors, seven serous cystadenomas, one pancreatic teratoma, three solid cystic tumors, 49 cases of chronic pancreatitis, 25 cases of focal pancreatitis, and seven cases of pancreatolithiasis). The probe was inserted via the papilla into the main pancreatic duct. In terms of resolution, IDUS at 20 MHz was able to image cystic lesions of less than 30 mm in diameter and solid lesions of less than 20 mm in diameter. With regard to vessels, IDUS was able to image the entire cross-section of the portal vein and other large veins. IDUS was useful in detecting carcinoma in situ and small tumors, in assessing the intraductal spread of the tumor and its pancreatic parenchymal invasion in mucin-producing tumors of the main duct, and in assessing the indications for surgery by revealing mural nodules in mucin-producing tumors of the ductal branches. IDUS was also useful in evaluating the feasibility of partial resection of the tumor in mucin-producing tumors of the ductal branches and pancreatic islet-cell tumors, in accurately locating multiple lesions in pancreatic islet-cell cancer, and in differentiating benign from malignant cases of localized stenosis of the main pancreatic duct related to pancreatic stenting. With IDUS, the site of pancreatic stones could be identified in order to assess the need for endoscopic treatments such as stenting of the pancreatic duct and the bile duct, and the use of pulsed-dye laser treatment under pancreatoscopy for pancreatic stones. Acute pancreatitis as a complication occurred in one of the 239 patients who underwent IDUS (0.4%). An awareness of the limitations and usefulness of IDUS in evaluating pancreatic diseases can contribute to the treatment of these conditions.

Aged↗
PubMed1997

Intracoronary stent implantation in native coronary arteries and saphenous vein grafts: a consecutive experience with six types of stents without prolonged anticoagulation.

OBJECTIVE: To analyze the results of implantation of six different intracoronary stents without the use of prolonged anticoagulation. MATERIAL AND METHODS: Between Mar. 30, 1993, and Jun. 30, 1995, 889 patients with 1,194 coronary or vein graft lesions underwent implantation of one of six types of stents-Palmaz-Schatz, Gianturco-Roubin, Wiktor, Micro, Cordis, or Wallstent. The patients were classified into seven groups on the basis of the type of stent that was implanted, including one group with combined use of two or more types of stents. Among the 851 patients with successful stent delivery and without major complications, 801 received only antiplatelet therapy, and 50 received a standard anticoagulation regimen. One-month clinical followup data were obtained in all patients, and clinical events were investigated. RESULTS: The mean number of stents was 1.8 per lesion and 2.4 per patient. Procedural success was achieved in 93% of the lesions. The clinical success rate at 1 month was 90%. Intravascular ultrasound assessment was performed in 90% of the lesions. The final minimal luminal cross-sectional area of the stent increased from 6.8 to 7.8 mm2 after intravascular ultrasound-guided optimization. Within 1 month, 16 stent thrombosis events (1.9%) occurred. No significant differences were noted in stent thrombosis rates among the various stent cohorts. Multivariate logistic regression analysis revealed that the final stent minimal luminal diameter measured by intravascular ultrasonography was the only variable associated with stent thrombosis. CONCLUSION: This study showed that six different stents could possibly be inserted without subsequent anticoagulation if optimal stent expansion and total lesion coverage were achieved.

Anticoagulants↗
PubMed1997

[Study on the surgical treatment for pulmonary metastasis from renal cell carcinoma].

BACKGROUND: Pulmonary resection for metastatic renal cell carcinoma were studied to assess the indication of surgical management. METHODS: Between January, 1981 and December 1994, 17 consecutive patients (14 men and 3 women) underwent complete pulmonary resection for metastatic renal carcinoma. Median age was 61 years (range, 45 to 73 years). Eleven were appeared lung metastasis after resection of primary tumor. Median time between nephrectomy and pulmonary resection was 32 months (range, 0 to 127 months). RESULTS: There were no operative deaths. One patient had solitary metastasis, 4 had two, 2 had three, 2 had four, one had seven, one had eight and 6 had more than twenty-two. Segmental resection was performed in 12 patients, lobectomy in 2, lobectomy and segmentectomy in 3 and segmentectomy for total lobes in 3. Four patients had another site operation of renal metastasis, brain tumor resection, chest wall and ribs resection, contra-lateral adrenalectomy and contralateral partial nephrectomy. Median follow-up was 44 months (range, 10 to 129 months). The cause specific survival rate and disease free survival after pulmonary resection was 55 and 48 percent at 5 years and 27 and 14 percent at 10 years, respectively. CONCLUSION: Pulmonary resection for metastatic renal cell carcinoma was considered effective in some selected slow-growing cases. Multiple and both lungs metastases is not contraindication and the patients under 10 metastatic focuses had good prognosis.

Aged↗
PubMed1997

Clinical Experiences of Steroid Targeting Therapy to Inner Ear for Control of Tinnitus.

We summarize our long-term clinical experiences with an inner-ear drug delivery system (DDS) for control of tinnitus. The inner-ear DDS consist of transtympanic perfusion of 2 or 4 mg dexamethasone to the round window via the middle ear. Therapeutic results of steroid targeting therapy to the inner ear were evaluated in 3,978 ears of 3,041 patients. Tinnitus improved in 75% of these patients immediately after treatment and in 68% after 6 months. The effects of such therapy on tinnitus varied depending on the underlying diseases. The improvement of tinnitus in the presence of labyrinthine hydrops was good, whereas the effects on noise- or drug-induced tinnitus were poor. Our results indicate that in high-tone tinnitus, the effects were poor, but they were good for low-pitched tinnitus. No correlation existed between the efficacy of management and loudness of the tinnitus. The dangers of perforating the eardrum and of inciting the discomfort of vertigo as a result of the transtympanic injection of dexamethasone are minimal. We believe that the transtympanic infusion technique is an effective DDS for control of inner-ear diseases and symptoms. This technique may be performed by any neurootologist in an outpatient clinic.

Journal Article↗
PubMed1997

Decreased pulmonary arterial endothelium-dependent relaxation in heartworm-infected dogs with pulmonary hypertension.

OBJECTIVE: To investigate the contractility of pulmonary arterial smooth muscle and the relation between pulmonary hypertension and endothelium-derived relaxing factor in canine heartworm disease. ANIMALS: 18 noninfected control and 9 heartworm-infected dogs. PROCEDURE: Mean pulmonary arterial blood pressure was measured in vivo, and tension of pulmonary arterial strips was measured by use of the isometric tension method. RESULTS: After phenylephrine (10(-5)M)-induced contraction of the pulmonary vascular smooth muscle, carbamylcholine chloride (CCh, 10(-6)M) caused more relaxation of the vascular smooth muscle of noninfected, dogs than that of heartworm-infected dogs. Furthermore, the degree of CCh-induced relaxation was inversely correlated with mean pulmonary arterial blood pressure in the noninfected and the heartworm-infected dogs. The CCh-induced relaxation was inhibited by pretreatment with NG-nitro-L-arginine methyl ester hydrochloride (10(-5)M), and in reversed dose-dependent manner by L-arginine (10(-4) to 3 x 10(-2)M). Sodium nitroprusside (10(-8) to 10(-5)M) caused a dose-dependent relaxation in all vessels, and there was no significant difference in the relaxation responses in both groups except at 10(-7)M for vessels with intact endothelium from noninfected dogs. CONCLUSION: The depression of endothelium-dependent relaxation is correlated with the pulmonary arterial blood pressure in heartworm-infected dogs, suggesting that the decrease is one of the essential factors for the genesis of pulmonary hypertension in canine filariasis.

Animals↗
PubMed1997

[Estimation of 123I-metaiodobenzylguanidine lung uptake in heart and lung diseases--with reference to lung uptake ratio and decrease of lung uptake].

123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy was performed in 64 patients with heart and lung diseases. Distribution of MIBG in the chest was evaluated by planar images, using counts ratios of the heart to the mediastinum (H/M) and the unilateral lung to the mediastinum (Lu/M). Most of patients with heart diseases showed obvious lung uptake of MIBG. The ratios of H/M were 1.75 +/- 0.20 in the group without heart failure and 1.55 +/- 0.19 in the group with heart failure. The ratios of Lu/M in the right and left lung were 1.56 +/- 0.16 and 1.28 +/- 0.16 in the group without heart failure. And those were 1.45 +/- 0.16 and 1.19 +/- 0.15 in the group with heart failure. But 3 patients complicated with chronic pulmonary emphysema and one patient with interstitial pneumonia due to dermatomyositis showed markedly decreased lung uptake. The ratios of Lu/M in the right and left lung of these patients were 1.20, 1.17; 1.17, 1.13; 1.01, 0.97 and 1.27, 0.94, respectively. These results suggest that the lung uptake of MIBG may reflect the state of pulmonary endothelial cell function in clinical situations, considering that it has been demonstrated that MIBG may be useful as a marker of pulmonary endothelial cell function in the isolated rat lung.

3-Iodobenzylguanidine↗
PubMed1997

[Myocardial scintigraphic studies with 123I-MIBG, 201Tl and 99mTc-PYP in patients with cardiac amyloidosis].

Myocardial scintigraphic studies, using 123I-metaiodobenzylguanidine (MIBG), 99mTc-pyrophosphate (PYP) and 201Tl were performed in 4 patients with cardiac amyloidosis. In MIBG myocardial images, 2 patients with familial amyloid polyneuropathy (FAP) showed complete or partial defect and the other 2 with primary amyloidosis had normal myocardial uptake of MIBG. In PYP myocardial images, diffuse myocardial uptake of PYP was mild in 2 patients with FAP and moderate in the other 2. 201Tl myocardial images revealed normal myocardial uptake of 201Tl in 2 patients with FAP and 1 with primary amyloidosis, and intense myocardial uptake in the other one with primary amyloidosis. These results suggest that myocardial scintigraphies with PYP and 201Tl may be useful for the detection of cardiac amyloidosis and estimation of its pathophysiology. And MIBG myocardial scintigraphy may provide useful information about sympathetic nerve abnormalities which vary with type of the fibril protein, clinical syndromes and disease process of cardiac amyloidosis.

3-Iodobenzylguanidine↗
PubMed1996

Protection of nonobese diabetic mice from autoimmune diabetes by reduction of islet mass before insulitis.

Nonobese diabetic mice spontaneously develop diabetes that is caused by autoimmune cell-mediated destruction of pancreatic beta cells. Here we report that surgical removal of 90% of pancreatic tissue before onset of insulitis induced a long-term diabetes-free condition in nonobese diabetic mice. Pancreatectomy after development of moderate insulitis had no effect on the course of diabetes. The effect of pancreatectomy was abrogated with subsequent development of diabetes by infusion of islet-cell-specific T lymphocytes and by transplantation of pancreatic islets. Lymphocytes from pancreatectomized diabetes-free mice exhibited low response to islet cells but responded normally to alloantigens. These results suggest that the islet cell mass plays a critical role in development of autoimmune diabetes.

Adoptive Transfer↗
PubMed1996

Characterization of a ligand for receptor protein-tyrosine kinase HTK expressed in immature hematopoietic cells.

HTK is a receptor tyrosine kinase that belongs to the Eph subfamily. An extensive screening using BIAcore system revealed that a colon cancer cell line, C-1, expressed the ligand for HTK. From the conditioned medium of C-1 cells, a soluble form of ligand was purified by receptor affinity chromatography, and the isolation of full-length cDNA revealed that this ligand is identical to the human HTK ligand (HTKL) previously reported. HTK receptor tyrosine phosphorylation was induced by membrane-bound or clustered soluble HTKL but not by unclustered soluble HTKL, indicating that HTKL requires cell-to-cell interaction for receptor activation. Binding analysis demonstrated that HTKL binds to HTK with a much higher affinity (Kd: 1.23 nM) than the other transmembrane-type ligand for Eph family, LERK-2/ELKL (Kd: 135 nM). The expression of HTK in cord blood cells was upregulated after the culture in the presence of stem cell factor. Clustered soluble HTKL stimulated the proliferation of sorted HTK+ cord blood cells and a hematopoietic cell line, UT-7/EPO from which HTK was isolated. These findings suggest the involvement of HTK-HTKL system in the proliferation of HTK+ hematopoietic progenitor cells in the hematopoietic environment.

Amino Acid Sequence↗
PubMed1996

A randomized comparison of combined ticlopidine and aspirin therapy versus aspirin therapy alone after successful intravascular ultrasound-guided stent implantation.

BACKGROUND: Previous studies have shown that it is feasible to withhold anticoagulation after a successful intracoronary stent procedure with a low incidence of stent thrombosis. The importance of specific antiplatelet agents when stenting is performed without anticoagulation is unknown. METHODS AND RESULTS: After successful intravascular ultrasound-guided stenting, 226 patients were randomly assigned to receive either aspirin therapy alone (n = 103) or a combination of ticlopidine and short-term aspirin therapy (n = 123). Primary angiographic and clinical end points were stent thrombosis, death, myocardial infarction, the need for postprocedure coronary artery bypass surgery or repeated angioplasty, and significant medication side effects requiring termination of the medication within the first month of a successful procedure. At 1 month, the rate of stent thrombosis was 2.9% in the aspirin only group and 0.8% in the ticlopidine-aspirin group (P = .2). Cumulative major clinical events after successful stenting occurred in 3.9% of the patients in the aspirin group and in 0.8% in the ticlopidine-aspirin group (P = .1). There were no medication side effects in the aspirin group; in the combined ticlopidine-aspirin group, medication side effects occurred in 3 patients (P = .2). CONCLUSIONS: At 1 month, there was no difference in the incidence of stent thrombosis or other clinical end points between the two poststent antiplatelet regimens. However, the relatively small size of the study and the low incidence of thrombosis events may have contributed to the failure to detect differences in angiographic and clinical end points between the two groups.

Aged↗
PubMed1996

Implantation of the peripheral Wallstent for diffuse lesions in coronary arteries and vein grafts.

The Wallstent (Schneider, Bulach, Switzerland) is available in different lengths without much compromise in flexibility and radial support compared to some other stents. We treated 24 patients (26 vessels) with diffuse coronary lesions or vein graft lesions with intravascular ultrasound-guided peripheral Wallstent implantation. Average balloon pressure during stent optimization was 16.4 +/- 2.7 atm. The stents could be successfully implanted in 24 vessels. Minimal lumen diameter and percent diameter stenosis after stenting were 3.60 +/- 0.62 mm and -8 +/- 13%, respectively. Average stent length was 63.7 +/- 22.7 mm. There was one procedure-related complication. After stenting, all patients were treated only with antiplatelet agents. During 1-month follow-up, there was one subacute stent thrombosis due to incomplete coverage of a distal dissection. These preliminary results show the feasibility of this novel approach in selected lesions.

Adult↗
PubMed1996

Acute recoil of Palmaz-Schatz stent: a rare cause of suboptimal stent implantation--report of two cases with intravascular ultrasound findings.

It is generally believed that the Palmaz-Schatz stent maintains a strong radial force, preventing stent recoil. However, the capacity to prevent recoil is largely governed by the hardness or resistance of the lesion. We report two cases of "acute Palmaz-Schatz stent recoil," documented by intravascular ultrasound, and suggest a novel treatment of this unusual problem.

Angioplasty, Balloon, Coronary↗
PubMed1996

Antiischemic effect of intracoronary diltiazem on myocardial ischemia during PTCA.

To evaluate the effect of intracoronary diltiazem on myocardial ischemia during percutaneous transluminal coronary angioplasty (PTCA), 38 patients were randomly assigned to receive inactive placebo (n = 19; group C) or a low dose (1 mg, n = 10; group D1), or a high dose (2 or 3 mg, n = 9; group D2) of diltiazem in a double-blind manner. The agent was administered directly into the coronary artery via a balloon catheter following a control balloon inflation. Chest pain score (maximum, 10) and the magnitude of ischemic ST elevation on standard and intracoronary electrocardiograms (ECGs) during a balloon inflation were assessed in the control and posttreatment periods. After the administration of diltiazem, the chest pain score was significantly decreased in group D1 (control: 5.1 +/- 3.6, posttreatment: 3.8 +/- 3.1, P < 0.01) and group D2 (3.4 +/- 2.5 vs 2.5 +/- 2.0, P < 0.01), but not in group C (4.1 +/- 3.1 vs 3.7 +/- 3.3, difference not significant). The magnitude of ST elevation relative to the control on standard and intracoronary ECGs was significantly smaller in groups D1 and D2 than in group C (standard ECG; D1: 51.8 +/- 10.6% of control, D2: 41.6 +/- 28.7% vs C: 93.3 +/- 15.6% and intracoronary ECG; D1: 47.1 +/- 11.7% of control, D2: 27.5 +/- 26.9% vs C: 94.6 +/- 29.3%, all P < 0.01). Although systolic blood pressure decreased slightly in groups D1 and D2, there was no significant correlation between the change in ST elevation and the change in the rate-pressure product. Pretreatment with a small dose of intracoronary diltiazem attenuated myocardial ischemia during PTCA and this pretreatment may enable us to perform balloon inflation for a longer period.

Angina Pectoris↗
PubMed1996

Enhancement of coronary reactive hyperemia in patients with ischemic myocardial tolerance during angioplasty.

The purpose of this study was to elucidate the effect of repeated brief coronary occlusions on reactive hyperemia during percutaneous transluminal coronary angioplasty (PTCA) in patients with or without ischemic tolerance. Seventeen patients undergoing PTCA for chronic stable angina were studied. Patients with well developed collateral vessels were excluded. After successful predilatation, coronary flow velocity was recorded with the use of a Doppler flow guide wire, and reactive hyperemia was assessed immediately after each of two 2-min coronary occlusions followed by 2 mins of reperfusion. The intracoronary electrocardiogram (icECG) was recorded via the flow guide wire placed in the center of the ischemic zone. Patients were divided into two groups: those who showed a reduction of ST elevation in the icECG recorded at the time of the second coronary occlusion (group I), and those who showed no difference in ST elevation between the two occlusions (group II). There were no significant differences in blood pressure, heart rate, or baseline coronary flow velocity between the two groups before the first occlusion, but the ST elevation at the time of the first coronary occlusion was greater in group I than in group II (8.9 +/- 6.2 versus 1.1 +/- 2.0 mm, P < 0.01). Reactive hyperemia was significantly greater after the second coronary occlusion than after the first in group I (22.1 +/- 15.8 versus 30.4 +/- 21.0 cm/s, P < 0.05), but it did not change in group II (25.6 +/- 13.0 versus 23.5 +/- 11.2 cm/s NS). Reactive hyperemia was enhanced in patients with ischemic tolerance who showed a reduction in St elevation in the icECG. These results suggest that observed reactive hyperemia does not necessarily reflect the severity of ischemia.

Aged↗
PubMed1996

Results of coronary stenting for restenosis.

OBJECTIVES: This study attempted to analyze immediate and long-term angiographic and clinical results of coronary stent implantation for restenosis in a consecutive group of patients. BACKGROUND: The rate of stent utilization in patients with coronary artery disease has increased exponentially in recent years. There are many unanswered questions about the use of stenting in patients with restenosis, particularly with respect to late clinical and angiographic results. METHODS: A total of 159 stents were implanted in 128 consecutive patients with 139 lesions (mean 1.3 stents/patient). A technique of optimal stent expansion was used in all patients, and intravascular ultrasound guidance with no subsequent anticoagulation was performed in 41 patients. RESULTS: Stent implantation was successful in 126 patients (98%). Four patients (3.1%) had complications (in two after successful stenting): death in one, emergency bypass surgery operation in two and subacute stent thrombosis in one. Stents were implanted with a final balloon size (mean +/- SD) of 3.5 +/- 0.5 mm and a mean maximal pressure of 11 +/- 4 atm (range 8 to 20). Angiographic restenosis occurred in 27 patients (25%). Regression analysis on clinical and angiographic variables for prediction of restenosis showed no statistical significance for any variable. Late events occurred in 23 patients (19%). The actuarial survival rate was 98% at 1 year and at 3 years, and the event-free survival rate including freedom from repeat angioplasty for restenosis was 95% and 76%, respectively. CONCLUSIONS: The late angiographic outcome, restenosis rate and total clinical events are favorable for selected patients undergoing stent implantation for the indication of restenosis.

Aged↗
PubMed1996

Dysfunction of cholinergic and dopaminergic neuronal systems in beta-amyloid protein--infused rats.

Accumulations of beta-amyloid protein are characteristic and diagnostic features of the brain of Alzheimer's disease patients; however, the physiological role of this protein in CNS is unknown. We have previously reported that continuous infusion of beta-amyloid protein into rat cerebral ventricle impairs learning ability and decreases choline acetyltransferase activity, a marker enzyme of cholinergic neuron. In this study, the effects of beta-amyloid protein infusion on the release of neurotransmitters in cholinergic and dopaminergic neuronal systems were investigated by using an in vivo brain microdialysis method. Nicotine-stimulated release of acetylcholine and dopamine in these animals was significantly lower than that in vehicle-infused rats. Further, dopamine release induced by high-K stimulation was decreased in beta-amyloid protein-infused rats compared with vehicle-infused rats. These results suggest that the release of the two transmitters, acetylcholine and dopamine, was decreased by beta-amyloid protein and that learning deficits observed in the beta-amyloid protein-infused rats are partly due to the impairment of neurotransmitter release. Furthermore, continuous infusion of beta-amyloid protein may be a useful method to produce the animal model of Alzheimer's disease.

Acetylcholine↗