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Biomedical subjects

A Itoh

Publications and source records attributed to A Itoh.

At least 19 recordsLinked to original sources
PubMed1995

Gadolinium-enhanced magnetic resonance imaging in acute myocardial infarction.

To investigate the clinical application of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) in the management of acute myocardial infarction (AMI), we examined 44 patients with AMI within 1 month after onset. Enhanced images were classified into 4 types: nontransmural (type 1), transmural and homogeneous (type 2), transmural and marginal (type 3), and no enhancement (type 4). Each enhancement pattern was correlated with angiographic and thallium-201 imaging results. The redistribution images of thallium were graded on a 4-point scale from 0 (normal) to 3 (markedly reduced or absent activity). The percentage of the perimeter affected by asynergy was obtained from the left ventriculogram. Peak creatine kinase and the percentage of asynergic perimeter were significantly higher in type 3 than in other type patients. End-diastolic volume index was significantly higher in type 3 than in type 2 patients. Left ventricular ejection fraction was lowest, and end-systolic volume index, thallium-201 score, and incidence of wall thinning on MRI were highest in type 3 patients. Therefore, the transmural and marginal enhancement pattern (type 3) was compatible with extensive myocardial infarction with infarct expansion and less viable myocardium. In the other types, the infarction was small to moderate in size and left ventricular function was well preserved. Thus, Gd-DTPA-enhanced MRI may be useful in the evaluation of left ventricular function and myocardial viability of the infarct region after AMI.

Aged↗
PubMed1995

Angioscopic prediction of successful dilatation and of restenosis in percutaneous transluminal coronary angioplasty. Significance of yellow plaque.

BACKGROUND: Coronary angiography has been used to assess the anatomy of coronary artery and intraluminal pathological changes. However, it has several limitations in its diagnostic quality and sensitivity in the detection of intraluminal details. Angioscopy has enabled coronary artery lumens to be visualized directly and fine intraluminal morphological changes to be detected. The information obtained by angioscopy is expected to provide new insights into the mechanisms and pathophysiology of transluminal coronary angioplasty. METHODS AND RESULTS: Forty-seven patients (39 men and 8 women) with stable angina were enrolled in the present study. Angioscopy was performed before and after angioplasty with a 0.68-mm angioscope with a double-guiding catheter system. The patients who were successfully evaluated by angioscopy were divided into two groups according to the color of the lesion: group 1, mainly yellow; and group 2, white. Angiographic, angioscopic, and clinical parameters in the two groups were compared. Detailed angioscopic findings were obtained in 36 of the 47 patients (77%) before percutaneous transluminal coronary angioplasty (PTCA) and in 24 of the 47 (51%) after PTCA. Yellow plaque were found in 13 of 36 (36%). Age, sex, presence of coronary risk factors, serum cholesterol level, and duration of angina showed no correlation with plaque color. The incidence rates of dissection and thrombi after angioplasty also were not different. Successful dilatation was achieved in 13 of 13 patients (100%) in group 1 and in 21 of 23 (91%) in group 2. The restenosis rate of group 1 was significantly lower than that in group 2 (16.7% versus 57.9%, P < .05). Cox proportional hazards model revealed that plaque color was the independent variable associated with restenosis after PTCA (P = .03). CONCLUSIONS: The restenosis rate after successful balloon angioplasty differs, with the color of the target lesion being significantly higher in patients with solely white plaque. Therefore, angioscopic findings are highly predictive of restenosis.

Angina Pectoris↗
PubMed1995

Correlation between the number of melanosomes, tyrosinase mRNA levels, and tyrosinase activity in cultured murine melanoma cells in response to various melanogenesis regulatory agents.

Tyrosinase is the rate limiting enzyme critically associated with melanin synthesis. The melanosomes are specialized membrane-bound organelles within melanocytic cells in which melanin polymers are ultimately deposited. To determine whether tyrosinase correlates with the number of melanosomes, we examined the relationship between tyrosinase activity, tyrosinase mRNA levels, and the number of melanosomes in B16 murine melanoma cells, using melanogenesis regulatory agents. 12-O-Tetradecanoylphorbol-13-acetate (TPA) or linoleic acid decreased tyrosinase activity, while dibutyryl cyclic adenosine monophosphate (dbcAMP) or palmitic acid increased it. The tyrosinase mRNA levels were not always correlated with tyrosinase activity, i.e., TPA down-regulated, dbcAMP upregulated, while linoleic acid or palmitic acid did not alter the message levels, indicating that fatty acid regulation of melanogenesis was due to post-transcriptional events. The number of melanosomes changed when agents which modulate the tyrosinase gene expression were added, since TPA decreased, dbcAMP increased, and linoleic acid or palmitic acid did not alter their number. These results suggest that the number of melanosomes changed in relation to tyrosinase mRNA level but not to tyrosinase activity in response to melanogenesis regulatory agents.

Animals↗
PubMed1995

Infrainguinal arterial reconstruction in end-stage renal disease.

A total of 14 infrainguinal revascularizations in 11 patients with end-stage renal disease resulting from diabetes mellitus were reviewed. Indications for surgery comprised gangrene or non-healing ulcerations in eight patients (11 limbs), ischaemic rest pain in two (two limbs) and disabling claudication in one (one limb). No graft failures occurred during the period of observation. There were two immediate postoperative deaths, one amputation, and four persistent non-healing foot ulcers. The remaining four patients showed improvement. Six deaths occurred, including two perioperative deaths. Four patients with non-healing ulcers died within 1 year and 10 months after revascularization, but their deaths were not associated with the foot ulcers. The cumulative patient survival rate was 42% at 1 year. Infrainguinal revascularization in patients with end-stage renal disease caused by diabetes mellitus is feasible when meticulous preoperative assessment and careful perioperative management are employed to minimize operative risk.

Aged↗
PubMed1995

Diet differentially regulates glucokinase and L-type pyruvate kinase gene expression in rat liver.

The regulation of gene expression of glucokinase (GK) and L-type pyruvate kinase (L-PK) in rat liver was investigated and compared with the previously reported regulation of lipogenic enzymes. Experiments were conducted in which the time courses and responses to diet quantity of mRNA concentrations and enzyme activities after refeeding a carbohydrate/protein diet (CP) to food-deprived rats were measured. The effects of dietary nutrients on the gene expression were investigated in rats refed either the CP diet, a carbohydrate diet without protein (C), a protein diet without carbohydrate (P), or a carbohydrate/protein/corn oil diet (CPF). The effects of the CPF diet on the gene expression after insulin treatment to diabetic rats were also investigated. After refeeding the CP diet, GK mRNA concentration and enzyme activity reached maximum levels in 2 h and 16-24 h, respectively, whereas those of L-PK peaked in 16 h and 48 h, respectively, similar timecourse to lipogenic enzymes. Moreover, GK mRNA concentrations were maximal in rats fed 20% of the ad libitum diet intake, and L-PK mRNA concentrations, like lipogenic enzyme mRNA, were maximal in rats fed approximately 50% of ad libitum intake. GK mRNA concentrations were significantly increased in parallel with an increase in plasma insulin and glucose concentrations. GK and L-PK mRNA and enzyme levels in rats fed the C diet were comparably induced to the levels in those fed the CP diet. L-PK mRNA induction by the CP diet was significantly reduced by dietary polyunsaturated fatty acids (CPF diet), whereas the GK mRNA induction was not significantly reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Beta 2 adrenergic receptor gene restriction fragment length polymorphism and bronchial asthma.

BACKGROUND: Beta 2 adrenergic dysfunction may be one of the underlying mechanisms responsible for atopy and bronchial asthma. The gene encoding the human beta 2 adrenergic receptor (beta 2ADR) has recently been isolated and sequenced. In addition, a two allele polymorphism of this receptor gene has been identified in white people. A study was carried out to determine whether this polymorphism is functionally important and has any relation to airways responsiveness, atopy, or asthma. METHODS: The subjects studied were 58 family members of four patients with atopic asthma. Restriction fragment length polymorphism (RFLP) with Ban-I digestion of the beta 2ADR gene was detected by a specific DNA probe with Southern blot analysis. Airways responses to inhaled methacholine and the beta 2 agonist salbutamol, the skin prick test, and serum IgE levels were also examined and correlated to the beta 2ADR gene RFLP. In addition, measurements of cAMP responses to isoproterenol in peripheral mononuclear cells were performed in 22 healthy subjects whose genotype for beta 2ADR was known. RESULTS: A two allele polymorphism (2.3 kb and 2.1 kb) of the beta 2ADR gene was detected in the Japanese population. Family members without allele 2.3 kb (homozygote of allele 2.1 kb) had lower airways responses to inhaled salbutamol than those with allele 2.3 kb. The incidence of asthma was higher in those without allele 2.3 kb than in those with allele 2.3 kb. The beta 2ADR gene RFLP had no relation to airways responses to methacholine and atopic status. cAMP responses in peripheral mononuclear cells of the subjects without allele 2.3 kb tended to be lower than those of the subjects with allele 2.3 kb. CONCLUSIONS: These results suggest that Ban-I RFLP of the beta 2ADR gene may have some association with the airways responses to beta 2 agonists and the incidence of bronchial asthma.

Adolescent↗
PubMed1995

Serum cardiac troponin T in patients with acute myocardial infarction. Detection of coronary reperfusion and prediction of cardiac function.

Serum troponin T, a myocardial contractile protein, has been reported to be a sensitive marker for the diagnosis of acute myocardial infarction. However, there have been few reports on its ability to detect coronary reperfusion and to predict left ventricular function in the chronic stage. Twenty two patients (20 males and 2 females, 61 +/- 10 y.o.) with acute myocardial infarction were enrolled in this study. They were divided into 2 groups, one with successful reperfusion (group A: n = 13) and one without reperfusion (Group B: n = 9) and the serial changes of their serum troponin T levels were evaluated. Serum myosin light chain was measured in another group of patients with acute myocardial infarction without history of old myocardial infarction (group C: n = 8). The slope of the logarithm of serum troponin T on a time-value curve was calculated from the time of admission to the first peak within 24 hours of the onset of acute myocardial infarction. The correlation coefficient between the late peak of serum troponin T and the left ventricular ejection fraction in 11 patients with first Q wave acute myocardial infarction was compared with that between the serum myosin light chain peak and the left ventricular ejection fraction in group C. 1) The slope of the logarithm of serum troponin T on the time-value curve in group A was greater than that in group B (0.57 +/- 0.45 vs. 0.22 +/- 0.16) (p < 0.05). 2) There was a good correlation between the late peak level of serum troponin T (78 +/- 10 hours after the onset) and the left ventricular ejection fraction in 11 patients with first Q wave acute myocardial infarction (r = -0.84, p < 0.01), which was similar to that of the serum myosin light chain peak and the left ventricular ejection fraction (r = -0.72, p < 0.05). On the other hand, there was no correlation between the peak level of serum creatine phosphokinase and the left ventricular ejection fraction (r = -0.55, NS). The serum troponin T levels 24, 36, 48 and 60 hours after the onset also correlated well with the left ventricular ejection fraction (r = -0.65, -0.7, -0.65 and -0.89, respectively). We conclude that the serial measurement of serum troponin T in patients with acute myocardial infarction is useful in the evaluation of left ventricular function in the chronic stage and that it is a potential non-invasive predictor of coronary reperfusion.

Aged↗
PubMed1994

Tissue specificity of mitochondrial F0F1-ATPase activity of Lilium longiflorum plant.

A large difference was found in the activities of oligomycin-sensitive mitochondrial F0F1-ATPase isolated from different tissues of Lilium longiflorum plants. The enzyme activity of F0F1-ATPase in pollen was the highest, while that in bulbs was the lowest. When ATPases were cross-reconstituted from F1-ATPases and F1-depleted submitochondrial particles (SMP), ATPases reconstituted from F1-depleted pollen SMP showed the higher activity regardless of the source of F1-ATPase. Fatty acid compositions of phospholipids in SMP were also different between bulbs and pollen. These suggest that the F0 portion and/or its environment are important for regulation of F0F1-ATPase activity in L. longiflorum plant.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

Ischemia-induced changes in catecholamine release and their mechanisms: a study using cultured bovine adrenal chromaffin cells.

Ischemia-induced changes in neurotransmitter release and their mechanisms were examined using cultured bovine adrenal chromaffin cells. When the cells were incubated in glucose-free media equilibrated with 0% O2/100% N2 (ischemia), ATP content decreased and reached the minimum level within 40 min. Control incubation was done in media equilibrated with 21% O2 in N2. After 10-min incubation under ischemic conditions, basal catecholamine (CA) release was elevated and the elevation persisted up to 90 min. High K(+)-evoked CA release was transiently enhanced at 10 min, but after that, it decreased to reach the minimum level at 60 min. At 10 min, cytosolic free Ca2+ concentration ([Ca2+]i) and 45Ca2+ uptake of the resting cells (basal values) and high K(+)-evoked increases in these two parameters were unchanged, but CA release from permeabilized cells in response to Ca2+ in media was augmented. After 60-min incubation under ischemic conditions, basal [Ca2+]i was elevated: the elevation was observed even in the absence of extracellular Ca2+. In contrast, high K(+)-evoked increases in [Ca2+]i and in 45Ca2+ uptake were suppressed, but basal 45Ca2+ uptake into intact cells and CA release from permeabilized cells were unchanged. These results suggest that in an early phase (10 min) of ischemia, both basal and stimulation-evoked CA release are augmented because of increased sensitivity of exocytotic machinery to Ca2+. In the late phase (60 min), basal CA release is augmented because of an increase in basal [Ca2+]i, which is due to accumulation of Ca2+ derived from intracellular Ca2+ pools: stimulation-evoked CA release is suppressed because of inhibition of stimulation-evoked increase in [Ca2+]i, which is due to functional disturbance of voltage-dependent Ca2+ channels.

Adenosine Triphosphate↗
PubMed1994

beta-Amyloid protein-induced Alzheimer's disease animal model.

To investigate the toxicity of beta-amyloid protein which consisted of senile plaques of Alzheimer's disease (AD), this was infused into cerebral ventricle for 14 days by using mini-osmotic pump. The performance of the water maze task in beta-amyloid protein-treated rats was impaired. Choline acetyltransferase activity significantly decreased in the frontal cortex and hippocampus. These results suggest that the deposition of beta-amyloid protein in the brain is related to the impairment of learning and cholinergic neuronal degeneration, and that beta-amyloid protein-treated rats could be used as an animal model for AD.

Alzheimer Disease↗
PubMed1994

Histamine modulates three types of K+ current in a human intestinal epithelial cell line.

K+ conductance species in a human intestinal epithelial cell line (Intestine 407) were studied in connection with their sensitivities to an intestinal secretagogue, histamine, using the tight-seal whole-cell patch-clamp technique. Applications of positive command pulses rapidly induced outward K+ currents. The conductance became progressively larger with increasing command voltages, exhibiting an outwardly rectifying current voltage relation. Inward K+ currents were also rapidly activated upon applications of hyperpolarizing pulses at potentials negative to the equilibrium potential of K+ (EK), and the conductance inwardly rectified. Application of a Ca2+ ionophore, ionomycin, brought about activation of additional K+ currents. An inhibitor of protein kinase C, polymyxin B, did not affect the ionomycin-induced response. Histamine (10-200 microM) also activated a similar K+ current which was abolished by cytosolic Ca2+ chelation. Under conditions where Ca2+ mobilization was minimized, histamine was found to significantly augment inwardly rectifying K+, but suppress outwardly rectifying K+, currents. Polymyxin B blocked these effects of histamine. An activator of protein kinase C, 1-oleoyl-2-acetylglycerol, mimicked the histamine effects. It is concluded that the intestinal epithelial cell has three distinct types of K+ conductance and that histamine modulates not only Ca(2+)-activated K+ conductance via Ca2+ mobilization, but also inward- and outward-rectifier K+ conductances via activation of protein kinase C.

Calcium↗
PubMed1994

Effects of subacute administration of methamphetamine and nicotine on locomotor activity in transgenic mice expressing the human tyrosine hydroxylase gene.

We produced transgenic (Tg) mice carrying the human tyrosine hydroxylase (TH) gene. To investigate differences in the dopaminergic (DAergic) neuronal activity between the Tg and nTg mice, we examined changes in the locomotor activity induced by methamphetamine (MAP) and nicotine (NIC), which enhances DA release and induces TH enzyme activation, respectively. Surprisingly, however, the intensity of MAP (2.5 mg/kg, once a day for 14 days)-induced hyperlocomotion in the nTg mice was greater than that in the Tg mice, and, furthermore, the Tg mice were less sensitive to subacute administration of NIC (0.5 mg/kg, once a day for 14 days) than the nTg mice. These results suggest that DAergic neuronal function is suppressed in Tg mice to compensate for the overexpression of TH.

Animals↗
PubMed1994

Nicotine reverses scopolamine-induced impairment of performance in passive avoidance task in rats through its action on the dopaminergic neuronal system.

Interest has recently focused on tobacco and/or nicotine in relation to senile dementia of the Alzheimer type because the population of patients with this disease among tobacco smokers is significantly smaller than in nonsmokers. We investigated whether, in relation to the dopaminergic neuronal system, nicotine was effective in ameliorating the impairment of performance in passive avoidance tasks in rats induced by scopolamine, an inhibitor of muscarinic acetylcholine receptors. Scopolamine and nicotine were coadministered to rats 30 min before the acquisition trial. Some rats received scopolamine alone; they showed much shorter step-through latency (STL) than the control group in the retention test. Nicotine significantly prolonged the decreased STL induced by scopolamine. The effects of nicotine were inhibited by the preadministration of mecamylamine, SCH 23390, and (-)sulpiride, which are nicotinic acetylcholine, D1, and D2 receptor antagonists, respectively. These results suggest that nicotine, by activating the nicotinic acetylcholinergic and dopaminergic neuronal systems, ameliorates the impairment of performance in the passive avoidance task induced by a muscarinic acetylcholine receptor blocker.

Animals↗
PubMed1994

Preparation of agglomerated crystals for direct tabletting and microencapsulation by the spherical crystallization technique with a continuous system.

Adhesive and cohesive properties of chlorpromazine hydrochloride (CP) crystals were modified to improve their powder processing, e.g., direct tabletting and microencapsulation, by agglomeration. Moreover, sustained-released gelling microcapsules of CP were devised to prolong the pharmacological effect. The spherical crystallization technique was applied to prepare agglomerates for direct tabletting and microencapsulation to use them as core materials. The ethanolic solution dissolving CP was poured into a stirred cyclohexane, yielding spherically agglomerated crystals. The resultant agglomerates were free-flowing and easily packable spheres with average diameters of 200 to 1000 microns. The agglomerates reserved the high compressibility of the original powder having a small particle size (14 microns). The compression behavior represented by Heckel's equation suggested that the agglomerates were disintegrated to individual primary crystals at low compression pressures, and then they were closely repacked and plastically deformed at higher pressures. After agglomeration, microencapsulation was continuously performed in the same batch by a phase separation method. Coacervate droplets produced by pouring cyclohexane into a dichloromethane solution, dissolving polyvinyl acetate as a coating polymer, were added to the crystallization system under stirring, to prepare the microcapsules. By filling the microcapsules in gelatin hard capsules or tabletting them, their drug release rates became retarded compared with the physical mixture treated in the same way, having the same formulation as the microcapsules. This phenomenon was due to the gelation of polyvinyl acetate of the microcapsules in the dissolution medium, whose glass transition temperature is very low. This novel sustained-release dosage form is termed "gelled microcapsules."

Adhesiveness↗
PubMed1994

A seroepidemiological study of hepatitis C virus (HCV) in an area with a high prevalence of chronic liver disease in the Kyushu district of Japan.

The incidence of hepatitis virus type C (HCV) in an area, Futase, of Iizuka city in Chikuho province in the northeastern part of Fukuoka prefecture in Kyushu, Japan, was estimated by screening sera for anti-HCV antibodies. Titers of anti human T-lymphotropic virus type I (HTLV-I) antibodies and hepatitis virus type B surface antigens (HBs) were also determined. The area of the present study is known to have a particularly high prevalence of chronic liver diseases, because coal mining was the key industry until a few decades ago. Also, in the old days it was rather isolated from the neighboring vicinities by surrounding mountains. The subjects of the present survey were 310 patients (117 males and 193 females) with various chronic diseases who visited Futase Social Insurance Hospital during a two year period from 1991 to 1992. Anti-HCV antibodies were detected in the sera of 55 patients, which is an overall positive rate of 18% (26% in male and 14% in female patients). This is extremely high compared to an estimated nationwide average positive rate of 1.6%. Even in 270 patients with normal liver function, the incidence was as high as 10%. The incidences were particularly high in groups of patients aged 40 through 49, 50 through 59 and 60 through 69, ranging from 20 to 23%, while they were as low as 13 and 17% in those aged 70 through 79 and 80 through 89 years, respectively. A high incidence, 57% was estimated for the patients with impaired liver function due to chronic liver diseases, especially in those concomitantly having diabetes mellitus (DM), 91%. The incidence of anti-HCV antibodies was the highest, 100%, in patients having both liver cirrhosis (LC) and DM. This was followed by those having chronic hepatitis (CH) and DM concomitantly and by those with LC alone, 86% each, and by those with CH alone 44%. Furthermore, the genotypes of the HCV in the sera of nine randomly selected carrier patients who had anti-HCV antibodies, even though they had diseases other than hepatic diseases and their liver functions were normal, were examined by the polymerase chain reaction method employing type-specific primers for DNA amplification. As a result, all the HCV strains were type II. On the other hand, there were no apparent differences in the incidences of HTLV-I in the area of the present study and in neighboring provinces of the same prefecture, Fukuoka.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

Intraductal ultrasonography for the examination of duodenal papillary region.

The purpose of this study was to provide basic criteria for interpreting images of the normal duodenal papillary region obtained by intraductal ultrasonography at the frequency of 20 MHz. Our in vitro examination of autopsy specimens from 15 patients revealed that the images could be classified into three patterns according to the spatial relationships between the duodenal muscularis propria and the bile duct, or the common duct. Oddi's muscle was clearly demonstrated surrounding the mucosa of the bile duct or the common duct, which was visualized as a hypoechoic layer. The images obtained using in vivo examination of 60 patients with pancreato-biliary disease via either the percutaneous or the peroral approach were similar to the images obtained in vitro. In eight patients with cancer of the papilla of Vater, the tumor was demonstrated clearly on intraductal sonograms. The intraductal imaging features of the normal papillary region were clarified, and the clinical usefulness of this technique in the evaluation of the tumor extent in patients with cancer of the papilla of Vater is suggested.

Ampulla of Vater↗