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Dive into the research topics where Hirokazu Okazaki is active.

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Featured researches published by Hirokazu Okazaki.


PLOS ONE | 2014

Plasma brain-derived neurotrophic factor and reverse dipping pattern of nocturnal blood pressure in patients with cardiovascular risk factors.

Manabu Kadoya; Hidenori Koyama; Akinori Kanzaki; Masafumi Kurajoh; Miki Hatayama; Jun Shiraishi; Hirokazu Okazaki; Takuhito Shoji; Yuji Moriwaki; Tetsuya Yamamoto; Masaaki Inaba; Mitsuyoshi Namba

Context Basic studies have shown that brain-derived neurotrophic factor (BDNF) has critical roles in the survival, growth, maintenance, and death of central and peripheral neurons, while it is also involved in regulation of the autonomic nervous system. Furthermore, recent clinical studies have suggested potential role of plasma BDNF in the circulatory system. Objective We investigated the mutual relationships among plasma BDNF, patterns of nocturnal blood pressure changes (dippers, non-dippers, extra-dippers, and reverse-dippers), and cardiac autonomic function as determined by heart rate variability (HRV). Design This was a cross-sectional study of patients registered in the Hyogo Sleep Cardio-Autonomic Atherosclerosis (HSCAA) Study from October 2010 to November 2012. Patients Two-hundred fifty patients with 1 or more cardiovascular risk factor(s) (obesity, smoking, presence of cardiovascular event history, hypertension, dyslipidemia, diabetes mellitus, chronic kidney disease) were enrolled. Results Plasma BDNF levels (natural logarithm transformed) were significantly (p = 0.001) lower in reverse-dipper patients (7.18±0.69 pg/ml, mean ± SD, n = 36) as compared to dippers (7.86±0.86 pg/ml, n = 100). Multiple logistic regression analysis showed that BDNF (odds ratios: 0.417, 95% confidence interval: 0.228–0.762, P = 0.004) was the sole factor significantly and independently associated with the reverse-dippers as compared with dippers. Furthermore, plasma BDNF level was significantly and positively correlated with the time-domain (SDNN, SDANN5, CVRR) and frequency-domain (LF) of HRV parameters. Finally, multiple logistic regression analyses showed that the relationship between plasma BDNF and the reverse-dippers was weakened, yet remained significant or borderline significant even after adjusting for HRV parameters. Conclusions Low plasma BDNF was independently associated with patients showing a reverse-dipper pattern of nocturnal blood pressure, in which an imbalance of cardiac autonomic function may be partly involved.


Internal Medicine | 2015

Partial HPRT Deficiency with a Novel Mutation of the HPRT Gene in Combination with Four Previously Reported Variants Associated with Hyperuricemia

Masafumi Kurajoh; Hidenori Koyama; Miki Hatayama; Hirokazu Okazaki; Takuhito Shoji; Yuji Moriwaki; Tetsuya Yamamoto; Tomitaka Nakayama; Mitsuyoshi Namba

A 15-year-old boy was referred to our department due to gout. The laboratory findings showed hyperuricemia with a decreased erythrocyte hypoxanthine phosphoribosyl transferase (HPRT) activity. The HPRT cDNA sequence was revealed to be 206A>T, which has not been previously reported. In addition, direct sequencing of genomic DNA showed the patient to possess four variants reported to be associated with hyperuricemia. This is the first case report of partial HPRT deficiency due to a novel HPRT mutation accompanied by variants associated with hyperuricemia. Combination treatment consisting of benzbromarone and febuxostat had a significant effect in reducing the urate level in our patient.


Journal of Cellular Biochemistry | 2015

Oncostatin M Promotes Osteoblastic Differentiation of Human Vascular Smooth Muscle Cells Through JAK3‐STAT3 Pathway

Yoshinori Kakutani; Atsushi Shioi; Tetsuo Shoji; Hirokazu Okazaki; Hidenori Koyama; Masanori Emoto; Masaaki Inaba

Vascular calcification is a clinically significant component of atherosclerosis and arises from chronic vascular inflammation. Oncostatin M (OSM) derived from plaque macrophages may contribute to the development of atherosclerotic calcification. Here, we investigated the stimulatory effects of OSM on osteoblastic differentiation of human vascular smooth muscle cells (HVSMC) derived from various arteries including umbilical artery, aorta, and coronary artery and its signaling pathway. Osteoblastic differentiation was induced by exposure of HVSMC to osteogenic differentiation medium (ODM) (10% fetal bovine serum, 0.1 μM dexamethasone, 10 mM β‐glycerophosphate and 50 μg/ml ascorbic acid 2‐phosphate in Dulbeccos modified Eagles medium [DMEM]). OSM significantly increased alkaline phosphate (ALP) activity and matrix mineralization in HVSMC from all sources. Osteoblast marker genes such as ALP and Runx2 were also up‐regulated by OSM in these cells. OSM treatment induced activation of STAT3 in HVSMC from umbilical artery as evidenced by immunoblot. Moreover, not only a JAK3 inhibitor, WHI‐P154, but also knockdown of JAK3 by siRNA prevented the OSM‐induced ALP activity and matrix mineralization in umbilical artery HVSMC. On the other hand, silencing of STAT3 almost completely suppressed OSM‐induced ALP expression and matrix mineralization in HVSMC from all sources. These data suggest that OSM promotes osteoblastic differentiation of vascular smooth muscle cells through JAK3/STAT3 pathway and may contribute to the development of atherosclerotic calcification. J. Cell. Biochem. 116: 1325–1333, 2015.


American Journal of Lifestyle Medicine | 2017

Nonpharmacological Management of Gout and Hyperuricemia: Hints for Better Lifestyle

Miki Kakutani-Hatayama; Manabu Kadoya; Hirokazu Okazaki; Masafumi Kurajoh; Takuhito Shoji; Hidenori Koyama; Zenta Tsutsumi; Yuji Moriwaki; Mitsuyoshi Namba; Tetsuya Yamamoto

We reviewed lifestyle factors that influence serum uric acid levels and risk of gout flare, and how to improve their deleterious effects. Since obesity increases uric acid and weight gain increases gout risk, weight reduction by daily exercise and limiting intake of excess calories is recommended. However, strenuous exercise, which causes adenine nucleotide degradation; starvation, which decreases uric acid excretion; and dehydration may raise the level of uric acid in serum and trigger gout. Increased intake of purine-rich foods, such as meat and seafood, raise the level of uric acid in serum and is associated with increased risk of gout, whereas dairy products, especially low-fat types, are associated with a lower risk of gout. Also, heavy alcohol drinking raises the uric acid level and increases the risk of gout through adenine nucleotide degradation and lactate production. Sweet fruits and soft drinks containing fructose should be moderated, since fructose may raise uric acid and increase gout risk through uric acid production and/or decreased excretion. On the other hand, the Mediterranean diet is recommended for gout patients, since it may also help prevent hyperuricemia. Furthermore, coffee and vitamin C supplementation could be considered as preventive measures, as those can lower serum uric acid levels as well as the risk of gout.


Internal Medicine | 2015

Anaplastic thyroid carcinoma accompanied by uncontrollable eosinophilia.

Jun Shiraishi; Hidenori Koyama; Miwako Seki; Miki Hatayama; Mariko Naka; Masafumi Kurajoh; Hirokazu Okazaki; Takuhito Shoji; Yuji Moriwaki; Tetsuya Yamamoto; Yasu-aki Tsuchida; Yoshitane Tsukamoto; Seiichi Hirota; Naoyoshi Onoda; Mitsuyoshi Namba

Anaplastic thyroid carcinoma is a rare disease, and cases associated with eosinophilia are even rarer. We herein report a case of anaplastic thyroid carcinoma accompanied by remarkable and uncontrollable eosinophilia. A 71-year-old man was diagnosed with end-stage anaplastic thyroid carcinoma. Throughout the aggressive clinical course of the cancer, eosinophilia dramatically progressed and became extremely refractory to steroid treatment. We measured the serum levels of hematopoietic cytokines potentially involved in eosinophilia, including granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-3 and IL-5. Although the GM-CSF level was moderately elevated, both the IL-3 and IL-5 levels were within the normal ranges. In this case, the patients eosinophilia may have been related to his severe dyspnea and was likely responsible for the allergic reaction to the anticancer drug. Therefore, it is essential to elucidate the etiology of eosinophilia in patients with thyroid cancer in order to improve the treatment for patients with anaplastic thyroid carcinoma.


Internal Medicine | 2016

Concomitant Cushing's Disease and Marked Hyperprolactinemia: Response to a Dopamine Receptor Agonist

Jun Shiraishi; Hidenori Koyama; Manabu Shirakawa; Reiichi Ishikura; Hirokazu Okazaki; Masafumi Kurajoh; Takuhito Shoji; Yuji Moriwaki; Tetsuya Yamamoto; Mitsuyoshi Namba

A 38-year-old woman was admitted to our hospital because of amenorrhea, multiple bone fractures, and a Cushingoid appearance. Endocrinological investigations revealed that she had co-existing Cushings disease and prolactinoma, with a serum level of prolactin (PRL) at 1,480 ng/mL, corticotropin (ACTH) at 81.3 pg/mL, and cortisol at 16.6 μg/dL. Due to the lack of indication for transsphenoidal surgery, cabergoline monotherapy was initiated. A 6-month course of treatment resulted in only subtle amelioration of hypercortisolism, while hyperprolactinemia was dramatically improved. In 5 cases of bihormonal (ACTH/PRL) pituitary macroadenoma reported in the English literature, 2 were initially treated with dopaminergic agonists with substantial effectiveness for both PRL and ACTH. We herein report an extremely rare case of bihormonal macroadenoma in which only PRL was responsive to treatment.


Atherosclerosis | 2015

Sleep, cardiac autonomic function, and carotid atherosclerosis in patients with cardiovascular risks: HSCAA study

Manabu Kadoya; Hidenori Koyama; Masafumi Kurajoh; Akinori Kanzaki; Miki Kakutani-Hatayama; Hirokazu Okazaki; Takuhito Shoji; Yuji Moriwaki; Tetsuya Yamamoto; Masanori Emoto; Masaaki Inaba; Mitsuyoshi Namba


Cardiovascular Diabetology | 2015

Plasma leptin level is associated with cardiac autonomic dysfunction in patients with type 2 diabetes: HSCAA study.

Masafumi Kurajoh; Hidenori Koyama; Manabu Kadoya; Mariko Naka; Akio Miyoshi; Akinori Kanzaki; Miki Kakutani-Hatayama; Hirokazu Okazaki; Takuhito Shoji; Yuji Moriwaki; Tetsuya Yamamoto; Masanori Emoto; Masaaki Inaba; Mitsuyoshi Namba


Osaka city medical journal | 2009

Phosphatidylinositol 3-kinase/Akt Pathway Regulates Inflammatory Mediators-induced Calcification of Human Vascular Smooth Muscle Cells

Hirokazu Okazaki; Atsushi Shioi; Kaname Hirowatari; Hidenori Koyama; Shinya Fukumoto; Eiji Ishimura; Yoshiki Nishizawa


Osteoporosis International | 2015

Increased undercarboxylated osteocalcin/intact osteocalcin ratio in patients undergoing hemodialysis

Yuki Nagata; Masaaki Inaba; Yasuo Imanishi; Hirokazu Okazaki; Shinsuke Yamada; Katsuhito Mori; Shigeichi Shoji; Hidenori Koyama; Senji Okuno

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Takuhito Shoji

Hyogo College of Medicine

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Yuji Moriwaki

Hyogo College of Medicine

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Jun Shiraishi

Kyoto Prefectural University of Medicine

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Miki Hatayama

Hyogo College of Medicine

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Manabu Kadoya

Hyogo College of Medicine

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