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Dive into the research topics where Toshiyuki Yamada is active.

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Featured researches published by Toshiyuki Yamada.


Lung | 1999

Serum Levels of Clara Cell 10-kDa Protein Are Decreased in Patients with Asthma

Noriharu Shijubo; Yoshihisa Itoh; Tetsuji Yamaguchi; F. Sugaya; Michio Hirasawa; Toshiyuki Yamada; Tadashi Kawai; Shosaku Abe

Abstract. Clara cell 10-kDa protein (CC10), the predominant product from nonciliated cells in the epithelial lining of bronchioles (Clara cells), has been shown to have immunomodulatory and antiinflammatory activity and may play a role in controlling airway inflammation. This study was designed to measure serum CC10 concentrations in healthy and asthmatic nonsmokers. Serum CC10 concentrations in asthmatic nonsmokers were significantly lower than in healthy nonsmokers. Asthmatic patients with a long duration of the disease (≥10 years) had significantly lower serum CC10 levels than those with a short duration of the disease (<10 years). There was no significant difference in serum CC10 levels in asthmatic patients between the time of the asthmatic attack and the stable condition. Serum CC10 levels may reflect decreased production of CC10 caused by remodeling of the small airways in asthma.


Medical Principles and Practice | 2010

Relationship between Reactive Oxygen Metabolites and Carotid Intima-Media Thickness in Subjects with Hypercholesterolemia

Kazuhiko Kotani; Harumi Koibuchi; Michiaki Miyamoto; Toshiyuki Yamada; Nobuyuki Taniguchi

Objective: It was the aim of this study to investigate whether there is any relationship between oxidative stress, as assessed by the diacron reactive oxygen metabolite (d-ROM) test, and carotid atherosclerosis among hypercholesterolemic patients. Subjects and Methods: A well-defined group of patients with type II hypercholesterolemia (n = 81, mean age 59 years) was studied to observe the correlation between the levels of serum d-ROMs and carotid artery intima-media thickness (IMT) using B-mode ultrasound, in relation to the traditional atherosclerotic risk factors (age, sex, smoking, body mass index, blood pressure, glucose and lipid panels). Results: The mean level in low-density lipoprotein cholesterol (LDL-C) in this population was 4.45 mmol/l, d-ROMs were 323.2 Carr U, and IMT was 0.91 mm. A multiple regression analysis revealed a positive and significant correlation between IMT and d-ROMs (β = 0.27, p < 0.05), along with age and LDL-C. Conclusion: These results indicate that the increased oxidative stress levels using the d-ROM test, independent of aging and increased LDL-C levels, may be associated with carotid atherosclerosis even in hypercholesterolemic patients.


BioMed Research International | 2013

Paired Measurements of Paraoxonase 1 and Serum Amyloid A as Useful Disease Markers

Kazuhiko Kotani; Toshiyuki Yamada; Alejandro Gugliucci

Paraoxonase 1 (PON1) and serum amyloid A (SAA) are proteins carried by high-density lipoprotein (HDL) particles. Among the HDL-associated protein molecules, SAA, an inflammation-related marker, and PON1, an antioxidant marker, tend to change in relatively clear opposite directions in physiological situations. In clinical chemistry, paired measurements of both markers may provide useful information to understand dysfunctional HDL in diseases with inflammation and oxidative stress conditions. Actually, limited clinical studies have suggested that the combined use of PON1 and SAA may be a tool for observing the pathophysiology of some disease entities. From the findings of experimental studies, PON1 appears to be cooperatively regulated by inflammation- and oxidative stress-related molecules linked with SAA regulation in humans. More studies remain to be performed to ascertain the value of paired measurements of both promising markers in clinical practice.


Hypertension Research | 2009

Comparative study of the cardio-ankle vascular index and ankle–brachial index between young Japanese and Mongolian subjects

Shuumarjav Uurtuya; Nobuyuki Taniguchi; Kazuhiko Kotani; Toshiyuki Yamada; Mikihiko Kawano; Nyamdavaa Khurelbaatar; Kouichi Itoh; Tserenkhuu Lkhagvasuren

Mongolian people have higher mortality and morbidity rates due to cardiovascular disease (CVD) than Japanese people. The cardio-ankle vascular index (CAVI) and ankle–brachial index (ABI) are both atherosclerosis-related indexes. Presently, there is no comparative information on CAVI and ABI among young subjects between Mongolian and Japanese people. A total of one hundred Mongolian (men: 39%, mean age: 20.9±2.2 years) and 115 Japanese volunteers (men: 39%, mean age: 22.0±1.8 years) were recruited from among university students. The body mass index (BMI), heart rate (HR), blood pressure (BP), CAVI, ABI, carotid intima–media thickness, blood total cholesterol (TC), glucose and C reactive protein levels were measured. The levels of BMI, HR and diastolic BP were significantly higher, and TC and glucose were significantly lower in the Mongolian subjects than in the Japanese subjects. The CAVI values (median (interquartile range): 6.5 (5.8–7.0) vs. 5.6 (5.2–6.0)) and ABI (1.11 (1.05–1.17) vs. 1.09 (1.05–1.15)) were significantly higher in the Mongolian subjects than in the Japanese subjects. The patterns of correlation between CAVI, ABI and other atherosclerotic parameters were different: in age-, gender- and BMI-adjustment correlation tests for CAVI and ABI, HR (r=−0.25 for CAVI and ABI) showed a correlation in the Mongolian subjects, and for ABI systolic BP (r=−0.28) showed a correlation in the Japanese subjects. These results suggest that Mongolian subjects may be at higher risk of CVD, even among younger individuals, than Japanese subjects.


Journal of Clinical Medicine Research | 2011

Influence of Physical Activity Intervention on Circulating Soluble Receptor for Advanced Glycation end Products in Elderly Subjects

Kazuhiko Kotani; Russell Caccavello; Naoki Sakane; Toshiyuki Yamada; Nobuyuki Taniguchi; Alejandro Gugliucci

Background Inflammation, often accompanied by oxidation, caused by advanced glycation end products (AGEs) may be quenched by the soluble receptor for AGEs (sRAGE). The present study aimed to investigate the influence of physical activity on circulating sRAGE, and the association between changes of circulating sRAGE and paraoxonase1 (PON1) activity (as an antioxidative enzyme) in a physical activity intervention study on an elderly subject cohort. Methods Serum sRAGE, PON1 activity and cardiometabolic variables were measured in 30 community-dwelling asymptomatic Japanese volunteers (15 men/15 women, mean age 65 years) in the pre- and post-phase of a 6-month interventional program designed to increase physical activity. Results The body mass index and sRAGE levels (1103 ± 496 to 1030 ± 437 ng/L, P < 0.05) were significantly reduced during the intervention period. In addition, the change of sRAGE was significantly and inversely correlated with that of PON1 activity, independent of the other cardiometabolic variables (β = - 0.511, P < 0.01). Conclusions This study showed a reduction of sRAGE levels, and an inverse correlation between sRAGE and PON1 activity, after the intervention study increasing physical activity on an elderly population. These findings represent a modest but significant modulation of sRAGE by this type of exercise intervention, which warranted future studies on the clinical relevance of sRAGE changes in physical activity. Keywords AGEs; RAGE; Paraoxonase1; Exercise; Atherosclerosis


Biochemical and Biophysical Research Communications | 2014

Effect of amino acid variations in the central region of human serum amyloid A on the amyloidogenic properties.

Hiroka Takase; Masafumi Tanaka; Sachiko Miyagawa; Toshiyuki Yamada; Takahiro Mukai

Human serum amyloid A (SAA) is a precursor protein of the amyloid fibrils that are responsible for AA amyloidosis. Of the four human SAA genotypes, SAA1 is most commonly associated with AA amyloidosis. Furthermore, SAA1 has three major isoforms (SAA1.1, 1.3, and 1.5) that differ by single amino acid variations at two sites in their 104-amino acid sequences. In the present study, we examined the effect of amino acid variations in human SAA1 isoforms on the amyloidogenic properties. All SAA1 isoforms adopted α-helix structures at 4°C, but were unstructured at 37°C. Heparin-induced amyloid fibril formation of SAA1 was observed at 37°C, as evidenced by the increased thioflavin T (ThT) fluorescence and β-sheet structure formation. Despite a comparable increase in ThT fluorescence, SAA1 molecules retained their α-helix structures at 4°C. At both temperatures, no essential differences in ThT fluorescence and secondary structures were observed among the SAA1 isoforms. However, the fibril morphologies appeared to differ; SAA1.1 formed long and curly fibrils, whereas SAA1.3 formed thin and straight fibrils. The peptides corresponding to the central regions of the SAA1 isoforms containing amino acid variations showed distinct amyloidogenicities, reflecting their direct effects on amyloid fibril formation. These findings may provide novel insights into the influence of amino acid variations in human SAA on the pathogenesis of AA amyloidosis.


Clinica Chimica Acta | 2014

Development of a new point-of-care testing system for measuring white blood cell and C-reactive protein levels in whole blood samples.

Kazuhiko Kotani; Takaomi Minami; Toshiaki Abe; Junji Sato; Nobuyuki Taniguchi; Toshiyuki Yamada

BACKGROUNDnWhite blood cell (WBC) count and C-reactive protein (CRP) level are the most common markers of inflammation. There is a growing need for point-of-care testing (POCT) of WBC and CRP, and more advances in convenient devices are required. We developed an analyzer-free POCT system for measuring WBC and CRP using a low volume blood sample.nnnMETHODSnThe POCT-WBC is based on the granulocyte esterase assay, while the POCT-CRP is based on the immunochromatographic assay. These kits were examined for precision as well as correlation with currently used popular commercial automated assays. The correlations were clinically analyzed in children with acute infection (n=62; mean age 4.2y). The correlations regarding the monitoring of values were further examined in several follow-up subjects.nnnRESULTSnThe POCT-WBC and POCT-CRP kits demonstrated good precision. POCT-WBC exhibited a significantly close correlation with those of the control assay (r=0.94, p<0.05). The results of POCT-CRP also exhibited a significantly close correlation with those of the control assay (r=0.94, p<0.05). In the follow-up study, the results of the respective kits were similar to those of the control assays.nnnCONCLUSIONSnThe POCT-WBC and POCT-CRP are promising tools for assessing infection in clinical practice.


Australasian Journal on Ageing | 2012

Oxidative stress and metabolic syndrome in a Japanese female population

Kazuhiko Kotani; Toshiyuki Yamada

Aim:u2002 One of the methods to evaluate oxidative stress in clinical medical settings is the reactive oxygen metabolites (d‐ROMs) test. While metabolic syndrome (MetS) is considered an oxidative condition, the oxidative status in MetS has not been fully examined using this test. The aim of the present study was to investigate the possible association between oxidative stress as evaluated by the d‐ROMs test and the MetS component number, in a Japanese female population.


Clinical Chemistry and Laboratory Medicine | 1996

Preparation and Characterization of Human Recombinant Protein 1/Clara Cell M r 10 000 Protein

Ryuta Okutani; Yoshihisa Itoh; Toshiyuki Yamada; Tetsuji Yamaguchi; Gurmukh Singh; Hitoshi Yagisawa; Tadashi Kawai

Protein 1, which is identical to human Clara cell M(r) 10(4) protein, is a homodimeric, low molecular mass protein (M(r) 14,000) and an effective inhibitor of phospholipase A2 activity. We have expressed this protein in E. coli and characterized its physiochemical and biological properties. Using a pET expression system, about 1.7 mg of purified recombinant protein 1 was obtained from 250 ml of E. coli culture. The amino-terminal sequence of recombinant protein 1 up to the 20th residue was identical to that of native protein 1 except for an extra methionine at the amino-terminus. On reversed-phase HPLC, recombinant protein 1 eluted at the same retention time as native protein 1. The dose-response curves of recombinant protein 1 and native protein 1 in an enzyme-linked immunosorbent assay for protein 1 were identical. Recombinant protein 1 inhibited both porcine pancreas and cobra venom phospholipase A2 activities. These results indicated that recombinant protein 1 is structurally and biologically identical to native protein 1. We found that recombinant protein 1 also inhibits phosphatidylinositol-specific phospholipase C activity.


Lipids in Health and Disease | 2010

The association between adiponectin, HDL-cholesterol and α1-antitrypsin-LDL in female subjects without metabolic syndrome

Kazuhiko Kotani; Toshiyuki Yamada; Nobuyuki Taniguchi

BackgroundOxidized low-density lipoprotein (LDL) may act as an atheroprotective (anti-atherosclerotic) agent under some conditions. While the α1-antitrypsin (AT)-LDL complex is considered a type of oxidized LDL, its clinical relevance remains unknown. The aim of the present study was to investigate the association between AT-LDL and anti-atherosclerotic variables such as HDL-cholesterol and adiponectin in subjects with and without metabolic syndrome (MetS).MethodsIn asymptomatic females (n = 194; mean age, 54 years) who were divided into non-MetS (n = 108) and MetS groups (n = 86), the fasting levels of serum AT-LDL, adiponectin and glucose/lipid panels were measured, in addition to body mass index (BMI) and blood pressure.ResultsThe MetS group showed significantly higher BMI, blood pressure, glucose and triglyceride levels as well as significantly lower levels of HDL-cholesterol and adiponectin than the non-MetS group. A multivariate-adjusted analysis revealed that in the non-MetS group, AT-LDL was significantly, independently and positively correlated with adiponectin (β = 0.297, P < 0.05), along with HDL-cholesterol (β = 0.217, P < 0.05). In the MetS group, AT-LDL was significantly, independently and positively correlated with LDL-cholesterol only (β = 0.342, P < 0.05).ConclusionsThese data suggest that AT-LDL may exert anti-atherosclerotic effects in female subjects without MetS. More studies are required to clarify the clinical roles of AT-LDL in relation to the pathophysiology of MetS.

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Junji Sato

Jichi Medical University

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Masafumi Tanaka

Kobe Pharmaceutical University

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Hiroka Takase

Kobe Pharmaceutical University

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Naoki Sakane

Kyoto Prefectural University of Medicine

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Takahiro Mukai

Kobe Pharmaceutical University

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