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Takeshi Yamamoto

Publications and source records attributed to Takeshi Yamamoto.

At least 19 recordsLinked to original sources
PubMed2026

A-liner: linear alignment visualizer for genome comparisons.

SUMMARY: A-liner is a flexible command-line tool for linear visualization of genome-scale sequence alignments, supporting outputs from multiple aligners and integrated visualization of annotations, highlights, quantitative tracks, and coordinate scales. It is applicable to a wide range of organisms, from bacteria to large eukaryotic genomes, and facilitates efficient generation of publication-ready comparative genome visualizations. AVAILABILITY AND IMPLEMENTATION: The source code and example output files for a-liner are available in the GitHub repository: https://github.com/mokuno3430/a-liner. A-liner v1.1.0 has been archived on Zenodo at https://doi.org/10.5281/zenodo.19702001.

Software↗
PubMed2006

Purification and characterization of alpha-glucosidase I from Japanese honeybee (Apis cerana japonica) and molecular cloning of its cDNA.

alpha-Glucosidase (JHGase I) was purified from a Japanese subspecies of eastern honeybee (Apis cerana japonica) as an electrophoretically homogeneous protein. Enzyme activity of the crude extract was mainly separated into two fractions (component I and II) by salting-out chromatography. JHGase I was isolated from component I by further purification procedure using CM-Toyopearl 650M and Sephacryl S-100. JHGase I was a monomeric glycoprotein (containing 15% carbohydrate), of which the molecular weight was 82,000. Enzyme displayed the highest activity at pH 5.0, and was stable up to 40 degrees C and in a pH-range of 4.5-10.5. JHGase I showed unusual kinetic features: the negative cooperative behavior on the intrinsic reaction on cleavage of sucrose, maltose, and p-nitrophenyl alpha-glucoside, and the positive cooperative behavior on turanose. We isolated cDNA (1,930 bp) of JHGase I, of which the deduced amino-acid sequence (577 residues) confirmed that JHGase I was a member of alpha-amylase family enzymes. Western honeybees (Apis mellifera) had three alpha-glucosidase isoenzymes (WHGase I, II, and III), in which JHGase I was considered to correspond to WHGase I.

Animals↗
PubMed2006

Transient leukocytopenia associated with a steep surge of pro-inflammatory cytokines in a patient with severe cardiogenic pulmonary edema.

Leukocytopenia can be caused by depressed production, increased peripheral destruction, or excessive peripheral pooling. Leukocyte margination is one of the mechanisms responsible for excessive peripheral pooling. A reversible leukocyte margination is caused by an increase in pro-inflammatory cytokines. However, there are limited data for this phenomenon in clinical conditions. We describe a case of unexpected transient leukocytopenia after exchanging an extracorporeal membrane oxygenation (ECMO) system used to treat severe cardiogenic pulmonary edema. To assess the cause of the leukocytopenia, the serum concentrations of pro-inflammatory cytokines and selectins were measured. The concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8 were markedly, but transiently, elevated in relation to the leukocytopenia. The transient leukocytopenia with pulmonary margination appeared to be caused by a steep surge of pro-inflammatory cytokines stimulated by hypoxia/reoxygenation during the exchange of the ECMO system. This case may suggest the mechanisms responsible for leukocytopenia in the clinical entity referred to as "systemic inflammatory response syndrome"

Chordae Tendineae↗
PubMed2006

Multiple forms of alpha-glucosidase in rice seeds (Oryza sativa L., var Nipponbare).

Two isoforms of alpha-glucosidases (ONG2-I and ONG2-II) were purified from dry rice seeds (Oryza sativa L., var Nipponbare). Both ONG2-I and ONG2-II were the gene products of ONG2 mRNA expressed in ripening seeds. Each enzyme consisted of two components of 6kDa-peptide and 88kDa-peptide encoded by this order in ONG2 cDNA (ong2), and generated by post-translational proteolysis. The 88kDa-peptide of ONG2-II had 10 additional N-terminal amino acids compared with the 88kDa-peptide of ONG2-I. The peptides between 6kDa and 88kDa components (26 amino acids for ONG2-I and 16 for ONG2-II) were removed by post-translational proteolysis. Proteolysis induced changes in adsorption and degradation of insoluble starch granules. We also obtained three alpha-glucosidase cDNAs (ong1, ong3, and ong4) from ripening seeds. The ONG1, ONG2, and ONG4 genes were situated in distinct locus of rice genome. The transcripts encoding ONG2 and ONG3 were generated by alternative splicing. Members of alpha-glucosidase multigene family are differentially expressed during ripening and germinating stages in rice.

Alternative Splicing↗
PubMed2006

Calbindin is predominantly expressed in nitrergic neurons in rat esophagus.

We used immunohistochemistry to investigate the colocalization pattern of calbindin D28k (Calb) with nitric oxide and acetylcholine in myenteric neurons in the rat esophagus and compared it to that in the ileum or distal colon. The proportion of Calb-immunoreactive (IR) neurons to the total neurons in the esophagus (8%) was lower than that in the ileum (38%) or distal colon (27%). A majority (84%) of the esophageal Calb-IR neurons were uniaxonal neurons. On the other hand, 88% and 66% of Calb-IR neurons in the ileum and distal colon, respectively, had Dogiel type II morphology, while most of the others were Dogiel type I neurons. Double immunolabeling indicated that most (87%) of the esophageal Calb-IR neurons were nitric oxide synthase (NOS) positive and a minority (21%) were choline acetyltransferase (ChAT) positive. Most (93% and 89%, respectively) of the Calb-IR neurons in the ileum and distal colon showed ChAT immunoreactivity and only a small number exhibited NOS immunoreactivity in the ileum and distal colon. In the esophagus, some of Calb-IR nerve endings surrounding the myenteric neurons were NOS positive, but no Calb immunoreactivity was found on the motor endplates of the striated muscles. Therefore, the present study revealed that most of the Calb-IR neurons in the esophagus are nitrergic, and it suggested that the Calb-IR neurons might be primarily involved in interneuronal roles in the esophageal nervous system.

Acetylcholine↗
PubMed2006

Path-integral virial estimator for reaction-rate calculation based on the quantum instanton approximation.

The quantum instanton approximation is a type of quantum transition-state theory that calculates the chemical reaction rate using the reactive flux correlation function and its low-order derivatives at time zero. Here we present several path-integral estimators for the latter quantities, which characterize the initial decay profile of the flux correlation function. As with the internal energy or heat-capacity calculation, different estimators yield different variances (and therefore different convergence properties) in a Monte Carlo calculation. Here we obtain a virial (-type) estimator by using a coordinate scaling procedure rather than integration by parts, which allows more computational benefits. We also consider two different methods for treating the flux operator, i.e., local-path and global-path approaches, in which the latter achieves a smaller variance at the cost of using second-order potential derivatives. Numerical tests are performed for a one-dimensional Eckart barrier and a model proton transfer reaction in a polar solvent, which illustrates the reduced variance of the virial estimator over the corresponding thermodynamic estimator.

Journal Article↗
PubMed2006

Usefulness of mitral annular velocity in predicting exercise tolerance in patients with impaired left ventricular systolic function.

Left ventricular (LV) diastolic function is 1 of the determinants of exercise tolerance. However, the relation between early diastolic velocity of the mitral annulus (Ea) obtained by tissue Doppler imaging and exercise tolerance is unknown in patients with impaired LV systolic function. To investigate the feasibility of evaluating exercise tolerance using tissue Doppler imaging, we studied 53 consecutive patients (mean age 58 +/- 14 years) with a LV ejection fraction of <50% (mean 37 +/- 9%). We measured the peak early diastolic velocity of transmitral flow (E) and Ea at the lateral border of the mitral annulus and then calculated the E/Ea ratio. After echocardiography, we measured the peak oxygen consumption and anaerobic threshold (AT) by cardiopulmonary exercise testing. Of all the echocardiographic parameters, the best correlation for AT was the E/Ea ratio (r = -0.74, p <0.001). Peak oxygen consumption correlated well with Ea and the E/Ea ratio (r = 0.64 and r = -0.68, respectively, p <0.001). The AT and peak oxygen consumption did not correlate with conventional Doppler indexes. Using an AT of 8 ml/min/kg as the cutoff to separate severe exercise intolerance from normal, mild, or moderate exercise intolerance, a receiver-operating characteristic curve showed that an E/Ea ratio of >11.3 had the best combination of sensitivity (88%) and specificity (86%). Exercise tolerance correlated with the E/Ea ratio in patients with impaired LV systolic function. In conclusion, the evaluation of LV diastolic function using tissue Doppler imaging is useful for predicting exercise tolerance in patients with heart failure.

Adult↗
PubMed2006

Arterial baroreflex sensitivity is a good predictor of inotropic responses to a phosphodiesterase inhibitor in human heart failure.

BACKGROUND: Experimental study has shown that blunted arterial baroreflex function markedly attenuated inotropic responses to a phosphodiesterase inhibitor (PDEI) even in normal hearts. However, whether arterial baroreflex function is related to the inotropic responsiveness to a PDEI has not been clarified in human heart failure (HF). HYPOTHESIS: The goal of this study was to examine the relationship between inotropic responses to a PDEI and arterial baroreflex sensitivity in human HF. METHODS: Twelve patients with HF were examined, and hemodynamic responses to milrinone (12.5, 25, and 50 microg/kg, intravenous injection) and arterial baroreflex sensitivity were assessed by pulse interval-left ventricular (LV) systolic pressure slope using nitroglycerin and phenylephrine. RESULTS: Milrinone (25 microg/kg) significantly increased LV dP/dt. Arterial baroreflex sensitivity was only one predictor of inotropic responses to milrinone by multivariate analysis; a strong positive correlation was also found between LV dP/dt and baroreflex sensitivity (y = 6.656X - 3.326, r = 0.93, p = 0.000). CONCLUSION: Inotropic effects of milrinone, a PDEI, correlated significantly with arterial baroreflex sensitivity, suggesting that the more baroreflex function was impaired, the more the inotropic effect of a PDEI was depressed in human HF.

Adult↗
PubMed2006

Fecal pancreatic elastase: a reproducible marker for severe exocrine pancreatic insufficiency.

BACKGROUND: In order to apply fecal pancreatic elastase for follow-up of exocrine pancreatic function in chronic pancreatitis and cystic fibrosis, we examined the sensitivity, specificity, and long-term variability of a new polyclonal antibody-based enzyme-linked immunosorbent assay (ELISA). METHODS: Patients with definite chronic pancreatitis (n = 23), probable or possible chronic pancreatitis (n = 14), autoimmune pancreatitis (n = 7), or acute pancreatitis (n = 11), and 51 healthy subjects and 11 healthy infants participated in this study. Pancreatic function was graded as normal (n = 3), mild (n = 18), moderate (n = 9), or severe (n = 18) exocrine insufficiency on the basis of secretin tests. Fecal pancreatic elastase was measured by a new ELISA. RESULTS: Fecal pancreatic elastase concentration in control subjects varied widely, with a median of 478 microg/g. The specificity of this test was 90.2% with a cutoff value of >200 microg/g. The sensitivities were 60.9% for detecting definite chronic pancreatitis, 76.5% for calcifying pancreatitis, 71.4% for autoimmune pancreatitis, and 7.1% for probable or possible chronic pancreatitis. The sensitivities were 16.7% for mild, 12.5% for moderate, and 72.2% for severe exocrine pancreatic insufficiency. Forty patients were reexamined after a median interval of 347 days. The fecal pancreatic elastase levels between the first and second tests were not significantly different. Two infants, 4.5 and 5 months old, had abnormally low values, but after a median of 304 days all infants showed normal levels (median, 444 microg/g). CONCLUSIONS: Fecal pancreatic elastase is a reproducible marker for severe exocrine pancreatic insufficiency. This test is valuable for longitudinal follow-up of exocrine pancreatic function.

Adult↗
PubMed2006

Intensive insulin therapy reduces small dense low-density lipoprotein particles in patients with type 2 diabetes mellitus: relationship to triglyceride-rich lipoprotein subspecies.

It remains unclear whether insulin improves dyslipidemia in patients with type 2 diabetes mellitus. Small dense low-density lipoprotein (sd-LDL) particles are recognized as a powerful risk factor for coronary heart disease and are often elevated in type 2 diabetes mellitus. We examined the effect of intensive insulin therapy on sd-LDL particles and triglyceride (TG)-rich lipoprotein subspecies. Intensive insulin therapy (insulin aspart [NovoRapid, Tokyo, Japan] before each meal and isophane insulin suspension at bedtime) was given to poorly controlled type 2 diabetic patients (n = 46) who were on high doses of sulfonylureas. Fasting serum samples were collected before and 14 days after the commencement of insulin therapy. Low-density lipoprotein size was measured by gradient gel electrophoresis, and the small dense LDL cholesterol (sd-LDL-C) concentration was measured by a new precipitation method. Chylomicrons (Svedberg flotation unit >400), very low-density lipoprotein 1 (VLDL1) (Sf, 60-400), and VLDL2 (Sf, 20-60) were separated by ultracentrifugation. Serum apolipoprotein B-48 and lipoprotein lipase levels were measured by the enzyme immunoassay method. Serum glucose and glycoalbumin levels were substantially decreased by insulin treatment. The LDL size increased (25.8-26.0 nm, P < .05) and the sd-LDL-C level was significantly reduced (44-34 mg/dL, P < .005). Apolipoproteins B-48 and C-III were decreased, whereas lipoprotein lipase was increased. Triglyceride levels in chylomicrons, VLDL1, and VLDL2 all showed a decrease. Changes of sd-LDL-C or LDL size were associated with changes of the TG levels in the major TG-rich lipoprotein subspecies. These results suggest that intensive insulin therapy decreases atherogenic sd-LDL particles by reducing TG in TG-rich lipoproteins. We did not find any specific relationship between VLDL1 and sd-LDL during insulin treatment.

Cholesterol, HDL↗
PubMed2006

Mechanisms of Disease: ryanodine receptor defects in heart failure and fatal arrhythmia.

Abnormal regulation of intracellular Ca(2+) by sarcoplasmic reticulum plays a part in the mechanism underlying contractile and relaxation dysfunction in heart failure (HF). The protein-kinase-A-mediated hyperphosphorylation of ryanodine receptors in the sarcoplasmic reticulum has been shown to cause the dissociation of FKBP12.6 (also known as calstabin-2) from ryanodine receptors in HF. In addition, several disease-linked mutations in the ryanodine receptors have been reported in patients with catecholaminergic polymorphic ventricular tachycardia or arrhythmogenic right ventricular cardiomyopathy type 2. The unique distribution of these mutation sites has led to the concept that the interaction among the putative regulatory domains within the ryanodine receptors has a key role in regulating channel opening. The knowledge gained from various studies of ryanodine receptors under pathologic conditions might lead to the development of new pharmacological or genetic strategies for the treatment of HF or cardiac arrhythmia. In this review, we focus on the role of the Ca(2+)-release channel, the ryanodine receptor, in the pathogenesis of HF and fatal arrhythmia, and the possibility of developing new therapeutic strategies for targeting this receptor.

Adrenergic beta-Antagonists↗
PubMed2006

AT1 receptor antagonist restores cardiac ryanodine receptor function, rendering isoproterenol-induced failing heart less susceptible to Ca2+ -leak induced by oxidative stress.

BACKGROUND: The Ca(2+) regulatory proteins in the sarcoplasmic reticulum (SR) play a key role in the pathogenesis of heart failure. In the present study the effect of chronic beta-receptor-stimulation on cardiac and SR functions was assessed, with or without angiotensin-II receptor antagonist treatment recently reported to have anti-beta-adrenergic activity. METHODS AND RESULTS: Rats were treated with isoproterenol with (+) or without (-) candesartan (CAN) and then SR vesicles were isolated from the left ventricular muscle. Both Ca(2+)-uptake and the amount of SR Ca(2+)-ATPase were significantly lower in the CAN (-) group than in the shams, but those were almost normally restored in the CAN (+). Although the level of the protein kinase A (PKA)-phosphorylation of the SR Ca(2+) release channel, known as the ryanodine receptor (RyR2), was elevated in the CAN (-), no Ca(2+)-leak was detected. However, SIN-1 (O(2) (-) donor) induced Ca(2+)-leak in the CAN (-) at a 10-fold lower dose than in the sham and CAN (+). In cardiomyocytes, SIN-1 decreased cell shortening and the peak Ca(2+) transient and prolonged time from peak to 70% decline in CAN (-), again at 10-fold lower dose than in the sham and CAN (+). CONCLUSION: Chronic beta-receptor-stimulation did not induce any Ca(2+)-leak from the SR, whereas Ca(2+)-leak was easily induced when oxidative stress was applied to the PKA-phosphorylated RyR2. Candesartan not only improved Ca(2+)-uptake, but also prevented PKA-phosphorylation, rendering the SR less susceptible to Ca(2+)-leak.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2006

Combined therapy with percutaneous coronary intervention and percutaneous aortic valvuloplasty under mechanical support for an elderly patient with cardiogenic shock.

Percutaneous aortic valvuloplasty is reportedly a useful tool for the management of critical and severe aortic stenosis with cardiogenic shock. However, early percutaneous coronary intervention for cardiogenic shock is beneficial for elderly patients with acute myocardial infarction. We describe a patient with critical aortic stenosis who presented with severe coronary stenosis of the left main trunk and the ostium of the right coronary artery. We performed percutaneous coronary intervention and percutaneous aortic valvuloplasty under intra-aortic balloon pump and percutaneous cardiopulmonary support. After these procedures, the cardiogenic shock was reversed, and the patient could be weaned from both intra-aortic balloon pump support and percutaneous cardiopulmonary support.

Aged, 80 and over↗
PubMed2006

Sustained clinical improvement of a patient with decompensated hepatitis B virus-related cirrhosis after treatment with lamivudine monotherapy.

Hepatitis B virus (HBV) infection, which causes liver cirrhosis and hepatocellular carcinoma, remains a major health problem in Asian countries. Recent development of vaccine for prevention is reported to be successful in reducing the size of chronically infected carriers, although the standard medical therapies have not been established up to now. In this report, we encountered a patient with decompensated HBV-related cirrhosis who exhibited the dramatic improvements after antiviral therapy. The patient was a 50-year-old woman. Previous conventional medical treatments were not effective for this patient, thus this patient had been referred to our hospital. However, the administration of lamivudine, a reverse transcriptase inhibitor, for 23 months dramatically improved her liver severity. During this period, no drug resistant mutant HBV emerged, and the serum HBV-DNA level was continuously suppressed. These virological responses were also maintained even after the antiviral therapy was discontinued. Moreover, both hepatitis B surface antigen and e antigen were observed to have disappeared in this patient. The administration of lamivudine to patients with HBV-related cirrhosis, like our present case, should be considered as an initial medical therapeutic option, especially in countries where liver transplantation is not reliably available.

Anti-HIV Agents↗
PubMed2006

Initial experiences of removal of intra-aortic balloon pumps with the Angio-Seal.

Angio-Seal, a vascular hemostasis device, has been shown to be safe and effective in rapidly achieving hemostasis after cardiac catheterization or coronary intervention. We propose that similar results can be obtained with Angio-Seal when removing an intra-aortic balloon pump (IABP). We studied 16 patients in whom Angio-Seal was utilized in IABP removals. The primary safety endpoint was a composite of major complications such as retroperitoneal bleeding, vessel occlusion, loss of distal pulses, vascular surgery or death, and minor complications such as hematoma (> 10 cm), AV fistula or pseudoaneurysm by 7 days after removal. The time-to-hemostasis was 2-5 minutes (mean 3.3 minutes). There were no instances of major or minor complications by the seventh day in any patients.

Adult↗
PubMed2006

[Progress in the diagnosis and treatment of acute coronary syndromes].

As the pathogenesis of acute coronary syndromes (ACS) has been well increasingly defined, there has been enormous progress in the diagnosis and treatment of ACS during the past 50 years. The previous terminology referring to the heterogeneity of the disease has shifted toward a unifying concept encompassing the wide spectrum of manifestations of ACS, subdivided for the purpose of therapeutic considerations into ST elevation myocardial infarction (MI), and non ST elevation ACS with or without cell necrosis (utilizing troponins), namely non ST elevation MI or unstable angina. The advent of coronary care units and the results of randomized clinical trials on reperfusion therapy, thrombolysis or percutaneous coronary intervention, and medical treatment with various pharmacological agents have substantially changed the therapeutic approach, and decreased in-hospital mortality.

Angina, Unstable↗